| Parent, Guarantor, Non-Guarantor Unaudited Consolidating Condensed Financial Statements - Consolidated Condensed Statements of Cash Flows (Detail) (USD $)In Thousands, unless otherwise specified
 | 9 Months Ended | 
      
        | Sep. 30, 2013 | Sep. 30, 2012 | 
      
        | Condensed Financial Statements [Line Items] |  |  | 
      
        | Repayments of long term debt | $ 125,000 | $ 125,000 | 
      
        | Cash flows from operating activities: |  |  | 
      
        | Net income | 17,064 | 57,265 | 
      
        | Adjustments to reconcile net income (loss) to net cash provided by operating activities: |  |  | 
      
        | Depreciation and amortization | 97,674 | 85,357 | 
      
        | Loss on extinguishment of debt | 5,218 | 1,766 | 
      
        | Gain on disposition of assets | (2,759) | (2,466) | 
      
        | Deferred income tax expense | 12,872 | 8,403 | 
      
        | Expenses not requiring cash | 9,928 | 15,724 | 
      
        | Equity in net earnings of subsidiaries | 0 | 0 | 
      
        | Change in other assets | (1,346) | 564 | 
      
        | Change in accounts receivable | (28,605) | 24,648 | 
      
        | Change in accrued income taxes | 2,877 | (3,049) | 
      
        | Change in liabilities | 12,412 | (10,185) | 
      
        | Net cash provided by operating activities | 125,335 | 178,027 | 
      
        | Cash flows from investing activities: |  |  | 
      
        | Capital expenditures | (102,856) | (147,658) | 
      
        | Proceeds from the sale of assets | 5,533 | 3,496 | 
      
        | Acquisition of ITS, net of cash acquired | (117,991) | 0 | 
      
        | Intercompany dividend payment |  | 0 | 
      
        | Net cash (used in) investing activities | (215,314) | (144,162) | 
      
        | Cash flows from financing activities: |  |  | 
      
        | Proceeds from debt issuance | 350,000 | 130,000 | 
      
        | Cash flows from operating activities: |  | 125,000 | 
      
        | Paydown on term note | (50,000) | (18,000) | 
      
        | Payment of debt issuance costs | (10,981) | (3,516) | 
      
        | Payments of debt extinguishment costs | 0 | (519) | 
      
        | Excess tax benefit from stock-based compensation | 531 | (572) | 
      
        | Intercompany advances, net | 0 | 0 | 
      
        | Net cash provided by (used in) financing activities | 164,550 | (17,607) | 
      
        | Net change in cash and cash equivalents | 74,571 | 16,258 | 
      
        | Cash and cash equivalents, beginning of year | 87,886 | 97,869 | 
      
        | Cash and cash equivalents, end of period | 162,457 | 114,127 | 
      
        | Parent [Member] |  |  | 
      
        | Condensed Financial Statements [Line Items] |  |  | 
      
        | Repayments of long term debt | 125,000 |  | 
      
        | Cash flows from operating activities: |  |  | 
      
        | Net income | 16,843 | 57,411 | 
      
        | Adjustments to reconcile net income (loss) to net cash provided by operating activities: |  |  | 
      
        | Depreciation and amortization | 0 | 0 | 
      
        | Loss on extinguishment of debt | 5,218 | 1,766 | 
      
        | Gain on disposition of assets | 0 | 0 | 
      
        | Deferred income tax expense | (2,860) | 5,940 | 
      
        | Expenses not requiring cash | 10,494 | 13,264 | 
      
        | Equity in net earnings of subsidiaries | (36,330) | (61,553) | 
      
        | Change in other assets | 3,045 | (32,874) | 
      
        | Change in accounts receivable | (899) | (291) | 
      
        | Change in accrued income taxes | 358 | (5,068) | 
      
        | Change in liabilities | 14,222 | 12,917 | 
      
        | Net cash provided by operating activities | 10,091 | (8,488) | 
      
        | Cash flows from investing activities: |  |  | 
      
        | Capital expenditures | 0 | 0 | 
      
        | Proceeds from the sale of assets | 0 | 0 | 
      
        | Acquisition of ITS, net of cash acquired | 0 |  | 
      
        | Intercompany dividend payment |  | (8,387) | 
      
        | Net cash (used in) investing activities | 0 | (8,387) | 
      
        | Cash flows from financing activities: |  |  | 
      
        | Proceeds from debt issuance | 350,000 | 130,000 | 
      
        | Cash flows from operating activities: |  | 125,000 | 
      
        | Paydown on term note | (50,000) | (18,000) | 
      
        | Payment of debt issuance costs | (10,981) | (3,516) | 
      
        | Payments of debt extinguishment costs |  | (519) | 
      
        | Excess tax benefit from stock-based compensation | 531 | (572) | 
      
        | Intercompany advances, net | (127,376) | 56,280 | 
      
        | Net cash provided by (used in) financing activities | 37,174 | 38,673 | 
      
        | Net change in cash and cash equivalents | 47,265 | 21,798 | 
      
        | Cash and cash equivalents, beginning of year | 42,251 | 55,670 | 
      
        | Cash and cash equivalents, end of period | 89,516 | 77,468 | 
      
        | Guarantor [Member] |  |  | 
      
        | Condensed Financial Statements [Line Items] |  |  | 
      
        | Repayments of long term debt | 0 |  | 
      
        | Cash flows from operating activities: |  |  | 
      
        | Net income | 27,612 | 63,505 | 
      
        | Adjustments to reconcile net income (loss) to net cash provided by operating activities: |  |  | 
      
        | Depreciation and amortization | 57,335 | 49,127 | 
      
        | Loss on extinguishment of debt | 0 | 0 | 
      
        | Gain on disposition of assets | (1,917) | (1,168) | 
      
        | Deferred income tax expense | 10,479 | 4,868 | 
      
        | Expenses not requiring cash | 591 | 689 | 
      
        | Equity in net earnings of subsidiaries | 0 | 0 | 
      
        | Change in other assets | 4,580 | 61,320 | 
      
        | Change in accounts receivable | (7,951) | 766 | 
      
        | Change in accrued income taxes | (85) | 1,832 | 
      
        | Change in liabilities | (2,116) | (21,430) | 
      
        | Net cash provided by operating activities | 88,528 | 159,509 | 
      
        | Cash flows from investing activities: |  |  | 
      
        | Capital expenditures | (66,956) | (139,618) | 
      
        | Proceeds from the sale of assets | 2,751 | 1,667 | 
      
        | Acquisition of ITS, net of cash acquired | (292) |  | 
      
        | Intercompany dividend payment |  | (4,357) | 
      
        | Net cash (used in) investing activities | (64,497) | (142,308) | 
      
        | Cash flows from financing activities: |  |  | 
      
        | Proceeds from debt issuance | 0 | 0 | 
      
        | Cash flows from operating activities: |  | 0 | 
      
        | Paydown on term note | 0 | 0 | 
      
        | Payment of debt issuance costs | 0 | 0 | 
      
        | Payments of debt extinguishment costs |  | 0 | 
      
        | Excess tax benefit from stock-based compensation | 0 | 0 | 
      
        | Intercompany advances, net | (13,781) | (13,507) | 
      
        | Net cash provided by (used in) financing activities | (13,781) | (13,507) | 
      
        | Net change in cash and cash equivalents | 10,250 | 3,694 | 
      
        | Cash and cash equivalents, beginning of year | 11,023 | 4,212 | 
      
        | Cash and cash equivalents, end of period | 21,273 | 7,906 | 
      
        | Non-Guarantor [Member] |  |  | 
      
        | Condensed Financial Statements [Line Items] |  |  | 
      
        | Repayments of long term debt | 0 |  | 
      
        | Cash flows from operating activities: |  |  | 
      
        | Net income | 8,939 | 42,011 | 
      
        | Adjustments to reconcile net income (loss) to net cash provided by operating activities: |  |  | 
      
        | Depreciation and amortization | 40,339 | 36,230 | 
      
        | Loss on extinguishment of debt | 0 | 0 | 
      
        | Gain on disposition of assets | (842) | (1,298) | 
      
        | Deferred income tax expense | 5,253 | (2,405) | 
      
        | Expenses not requiring cash | (1,157) | 1,770 | 
      
        | Equity in net earnings of subsidiaries | 0 | 0 | 
      
        | Change in other assets | (8,971) | (27,882) | 
      
        | Change in accounts receivable | (19,755) | 24,173 | 
      
        | Change in accrued income taxes | 2,604 | 187 | 
      
        | Change in liabilities | 306 | (1,672) | 
      
        | Net cash provided by operating activities | 26,716 | 71,114 | 
      
        | Cash flows from investing activities: |  |  | 
      
        | Capital expenditures | (35,900) | (8,040) | 
      
        | Proceeds from the sale of assets | 2,782 | 1,829 | 
      
        | Acquisition of ITS, net of cash acquired | (117,699) |  | 
      
        | Intercompany dividend payment |  | (31,364) | 
      
        | Net cash (used in) investing activities | (150,817) | (37,575) | 
      
        | Cash flows from financing activities: |  |  | 
      
        | Proceeds from debt issuance | 0 | 0 | 
      
        | Cash flows from operating activities: |  | 0 | 
      
        | Paydown on term note | 0 | 0 | 
      
        | Payment of debt issuance costs | 0 | 0 | 
      
        | Payments of debt extinguishment costs |  | 0 | 
      
        | Excess tax benefit from stock-based compensation | 0 | 0 | 
      
        | Intercompany advances, net | 141,157 | (42,773) | 
      
        | Net cash provided by (used in) financing activities | 141,157 | (42,773) | 
      
        | Net change in cash and cash equivalents | 17,056 | (9,234) | 
      
        | Cash and cash equivalents, beginning of year | 34,612 | 37,987 | 
      
        | Cash and cash equivalents, end of period | 51,668 | 28,753 | 
      
        | Eliminations [Member] |  |  | 
      
        | Condensed Financial Statements [Line Items] |  |  | 
      
        | Repayments of long term debt | 0 |  | 
      
        | Cash flows from operating activities: |  |  | 
      
        | Net income | (36,330) | (105,662) | 
      
        | Adjustments to reconcile net income (loss) to net cash provided by operating activities: |  |  | 
      
        | Depreciation and amortization | 0 | 0 | 
      
        | Loss on extinguishment of debt | 0 | 0 | 
      
        | Gain on disposition of assets | 0 | 0 | 
      
        | Deferred income tax expense | 0 | 0 | 
      
        | Expenses not requiring cash | 0 | 1 | 
      
        | Equity in net earnings of subsidiaries | 36,330 | 61,553 | 
      
        | Change in other assets | 0 | 0 | 
      
        | Change in accounts receivable | 0 | 0 | 
      
        | Change in accrued income taxes | 0 | 0 | 
      
        | Change in liabilities | 0 | 0 | 
      
        | Net cash provided by operating activities | 0 | (44,108) | 
      
        | Cash flows from investing activities: |  |  | 
      
        | Capital expenditures | 0 | 0 | 
      
        | Proceeds from the sale of assets | 0 | 0 | 
      
        | Acquisition of ITS, net of cash acquired | 0 |  | 
      
        | Intercompany dividend payment |  | 44,108 | 
      
        | Net cash (used in) investing activities | 0 | 44,108 | 
      
        | Cash flows from financing activities: |  |  | 
      
        | Proceeds from debt issuance | 0 | 0 | 
      
        | Cash flows from operating activities: |  | 0 | 
      
        | Paydown on term note | 0 | 0 | 
      
        | Payment of debt issuance costs | 0 | 0 | 
      
        | Payments of debt extinguishment costs |  | 0 | 
      
        | Excess tax benefit from stock-based compensation | 0 | 0 | 
      
        | Intercompany advances, net | 0 | 0 | 
      
        | Net cash provided by (used in) financing activities | 0 | 0 | 
      
        | Net change in cash and cash equivalents | 0 | 0 | 
      
        | Cash and cash equivalents, beginning of year | 0 | 0 | 
      
        | Cash and cash equivalents, end of period | $ 0 | $ 0 |