Other Financial Statement Disclosures (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Unsecured debt [Member] Senior Notes due 2017 [Member]	Sep. 30, 2012 Unsecured debt [Member] Senior Notes due 2019 [Member]	Sep. 30, 2012 Unsecured debt [Member] Senior Notes due 2022 [Member]	Sep. 30, 2012 Carrying Value [Member]	Dec. 31, 2011 Carrying Value [Member]	Sep. 30, 2012 Fair Value [Member]	Dec. 31, 2011 Fair Value [Member]
Fair values of Financial Instruments [Abstract]
5% Senior Notes, due 2017								$ 398,606,000	$ 398,394,000	$ 440,678,000	$ 420,019,000
7.875% Senior Notes, due 2019								497,759,000	497,511,000	618,846,000	588,495,000
4.875% Senior Notes, due 2022								496,786,000	0	535,451,000	0
Title XI notes								0	238,453,000	0	257,185,000
Total								1,393,151,000	1,134,358,000	1,594,975,000	1,265,699,000
Debt Instrument [Line Items]
Stated interest rate (in hundredths)					5.00%	7.875%	4.875%
Maturity of debt					2017	2019	2022
Supplemental Cash Flow Information [Abstract]
Accrued capital expenditures			41,300,000	38,700,000
Interest capitalized in connection with rig construction projects	8,300,000	13,900,000	22,400,000	39,600,000
Income Taxes [Abstract]
U.S. statutory tax rate (in hundredths)			35.00%
U.K. statutory tax rate (in hundredths)			24.00%
Tax benefit	8,533,000	(3,876,000)	2,858,000	(1,010,000)
Material Charges and Other Operating Expenses [Abstract]
Redomestication expenses	1,895,000	0	11,696,000	0
Repair costs for EXL I	8,855,000	0	8,855,000	0
Share-based compensation for retiring employee	2,298,000	0	2,298,000	0
Pension settlement loss	5,126,000	0	5,126,000	0
Steel impairment costs	0	0	2,896,000	0
Settlement of litigation - Loss of Rowan Halifax	0	20,000	0	6,120,000
Material charges and other operating expenses	$ 18,174,000	$ 20,000	$ 30,871,000	$ 6,120,000