Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenues:
Contract drilling	$ 3,254,313	$ 3,229,736	$ 3,536,579
Revenues related to reimbursable expenses	68,106	93,238	94,705
Total revenues	3,322,419	3,322,974	3,631,284
Operating expenses:
Contract drilling, excluding depreciation	1,548,502	1,391,086	1,223,771
Reimbursable expenses	66,052	91,240	93,097
Depreciation	398,612	393,177	346,446
General and administrative	65,310	66,600	62,913
Bad debt (recovery) expense	(6,713)	(9,789)	9,746
Gain on disposition of assets	(4,758)	(34,714)	(7,902)
Total operating expenses	2,067,005	1,897,600	1,728,071
Operating income	1,255,414	1,425,374	1,903,213
Other income (expense):
Interest income	6,688	2,909	4,497
Interest expense	(73,137)	(90,698)	(49,610)
Foreign currency transaction gain (loss)	(8,588)	1,369	11,483
Other, net	(1,086)	(2,938)	(1,152)
Income before income tax expense	1,179,271	1,336,016	1,868,431
Income tax expense	(216,729)	(380,559)	(492,212)
Net income	$ 962,542	$ 955,457	$ 1,376,219
Earnings per share:
Basic	$ 6.92	$ 6.87	$ 9.90
Diluted	$ 6.92	$ 6.87	$ 9.89
Weighted-average shares outstanding:
Shares of common stock	139,027	139,026	139,007
Dilutive potential shares of common stock	11	44	90
Total weighted-average shares outstanding	139,038	139,070	139,097
Cash dividends declared per share of common stock	$ 3.50	$ 5.25	$ 8.00