CONSOLIDATED CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands |
Jun. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Statement of Financial Position [Abstract] | ||
| Allowance for bad debts | $ 8,192 | $ 8,694 |
| Accumulated depreciation and amortization on property, plant and equipment | $ 1,360,990 | $ 1,302,380 |
| X | ||||||||||
- Definition Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition A valuation allowance relating to a written agreement to receive money (at a specified future date(s) within one year from the reporting date (or the normal operating cycle, whichever is longer), consisting of principal as well as any accrued interest) for the portion that is expected to be uncollectible. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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