Industry Segment Information (Revenue From Different Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Revenues:
Contract drilling	$ 145,561		$ 140,193		$ 458,945		$ 381,982
Elimination of inter-segment revenue	(12,141)		(11,266)		(37,747)		(39,884)
Contract drilling net of inter-segment revenue	133,420		128,927		421,198		342,098
Oil and natural gas	131,420		134,897		397,745		376,393
Gas gathering and processing	70,394		79,919		210,550		200,821
Elimination of inter-segment revenue	(17,459)		(19,231)		(50,573)		(56,001)
Gas gathering and processing net of inter-segment revenue	52,935		60,688		159,977		144,820
Other	(15)		(667)		1,160		(566)
Total revenues	317,760		323,845		980,080		862,745
Operating income
Contract drilling	40,338		35,105		134,558		94,679
Oil and natural gas	50,784		58,104		22,997	[1]	150,584
Gas gathering and processing	784		3,372		7,404		14,050
Total operating income	91,906	[2]	96,581	[2]	164,959	[2]	259,313	[2]
General and administrative expense	(8,434)		(7,800)		(23,814)		(22,188)
Interest expense, net	(7,087)		(1,351)		(11,455)		(2,078)
Other	(15)		(667)		1,160		(566)
Income before income taxes	$ 76,370		$ 86,763		$ 130,850		$ 234,481

[1] In June 2012, we had a non-cash ceiling test write-down of $115.9 million pre-tax ($72.1 million, net of tax).

[2] Total operating income is total operating revenues less operating expenses, depreciation, depletion, amortization and impairment and does not include non-operating revenues, general corporate expenses, interest expense or income taxes.