Industry Segment Information (Revenue From Different Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Revenues:
Contract drilling	$ 160,925		$ 129,281		$ 313,384		$ 241,789
Elimination of inter-segment revenue	(14,053)		(14,098)		(25,606)		(28,618)
Contract drilling net of inter-segment revenue	146,872		115,183		287,778		213,171
Oil and natural gas	132,553		131,662		266,325		241,496
Gas gathering and processing	65,901		63,894		140,156		120,902
Elimination of inter-segment revenue	(16,154)		(19,526)		(33,114)		(36,770)
Gas gathering and processing net of inter-segment revenue	49,747		44,368		107,042		84,132
Other	720		282		1,175		101
Total revenues	329,892		291,495		662,320		538,900
Operating income (loss)
Contract drilling	50,815		31,727		94,220		59,574
Oil and natural gas	(73,753)	[1]	53,695		(27,787)	[1]	92,480
Gas gathering and processing	2,072		3,742		6,620		10,678
Total operating income (loss)	(20,866)	[2]	89,164	[2]	73,053	[2]	162,732	[2]
General and administrative expense	(8,376)		(7,496)		(15,380)		(14,388)
Interest expense, net	(2,542)		(673)		(4,368)		(727)
Other	720		282		1,175		101
Income (loss) before income taxes	$ (31,064)		$ 81,277		$ 54,480		$ 147,718

[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 (loss) 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.