Industry Segment Information (Revenue From Different Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Industry Segment Information [Abstract]
Contract drilling	$ 152,459		$ 112,508
Elimination of inter-segment revenue	(11,553)		(14,520)
Contract drilling net of inter-segment revenue	140,906		97,988
Oil and natural gas	133,772		109,834
Gas gathering and processing	74,255		57,008
Elimination of inter-segment revenue	(16,960)		(17,244)
Gas gathering and processing net of inter-segment revenue	57,295		39,764
Other	455		(181)
Total revenues	332,428		247,405
Contract drilling	43,405		27,847
Oil and natural gas	45,966		38,785
Gas gathering and processing	4,548		6,936
Total operating income	93,919	[1]	73,568	[1]
General and administrative expense	(7,004)		(6,892)
Interest expense, net	(1,826)		(54)
Other	455		(181)
Income before income taxes	$ 85,544		$ 66,441

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