|
Fair Value of Financial Instruments - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2011
U.S. Drilling Segment [Member]
|
Dec. 31, 2011
Fair Value, Inputs, Level 3
|
Sep. 30, 2012
Fair Value, Inputs, Level 2
|
Dec. 31, 2011
Fair Value, Inputs, Level 2
|
|
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||||
| Carrying amount of interest rate swap agreements | $ 0.1 | $ 0.1 | ||
| Non-cash pre-tax impairment charge | 170.0 | |||
| Non-cash pre-tax impairment charge after tax | 109.1 | |||
| Fair value | $ 169.5 | |||
| Percentage of discount on expected future cash flows | 10.00% |
| X | ||||||||||
|
- Definition
Non-cash pre-tax impairment charge after tax. No definition available.
|
| X | ||||||||||
|
- Definition
Rate for discounting expected future cash flows to decide fair value of property. No definition available.
|
| X | ||||||||||
|
- Definition
The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Details
|
| X | ||||||||||
|
- Definition
Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software, net of accumulated depreciation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|