CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues:
Contract drilling	$ 2,936,066	$ 3,254,313	$ 3,229,736
Revenues related to reimbursable expenses	50,442	68,106	93,238
Total revenues	2,986,508	3,322,419	3,322,974
Operating expenses:
Contract drilling, excluding depreciation	1,537,224	1,548,502	1,391,086
Reimbursable expenses	48,778	66,052	91,240
Depreciation	392,913	398,612	393,177
General and administrative	64,640	65,310	66,600
Impairment of assets	62,437
Bad debt recovery	(1,018)	(6,713)	(9,789)
Gain on disposition of assets	(80,844)	(4,758)	(34,714)
Total operating expenses	2,024,130	2,067,005	1,897,600
Operating income	962,378	1,255,414	1,425,374
Other income (expense):
Interest income	4,910	6,668	2,909
Interest expense	(46,216)	(73,137)	(90,698)
Foreign currency transaction gain (loss)	(1,999)	(8,588)	1,369
Other, net	(992)	(1,086)	(2,938)
Income before income tax expense	918,081	1,179,271	1,336,016
Income tax expense	(197,604)	(216,729)	(380,559)
Net income	$ 720,477	$ 962,542	$ 955,457
Earnings per share:
Basic	$ 5.18	$ 6.92	$ 6.87
Diluted	$ 5.18	$ 6.92	$ 6.87
Weighted-average shares outstanding:
Shares of common stock	139,029	139,027	139,026
Dilutive potential shares of common stock	19	11	44
Total weighted-average shares outstanding	139,048	139,038	139,070
Cash dividends declared per share of common stock	$ 3.50	$ 3.50	$ 5.25