Drilling and Other Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2011

Drilling and Other Property and Equipment [Abstract]

Summary of Cost and accumulated depreciation of drilling and other property and equipment

	December 31,
	2011			2010
	(In thousands)
Drilling rigs and equipment	$	7,431,713		$	7,163,196
Construction work-in-progress		504,805			—
Land and buildings		60,926			56,536
Office equipment and other		49,035			44,689
Cost		8,046,479			7,264,421
Less accumulated depreciation		(3,379,010	)		(2,980,629)
Drilling and other property and equipment, net	$	4,667,469		$	4,283,792