Industry Segment Information (Revenue From Different Segments) (Details) (USD $) In Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Industry Segment Information
Contract drilling	$ 129,281		$ 82,046		$ 241,789		$ 149,547
Elimination of inter-segment revenue	(14,098)		(9,985)		(28,618)		(16,632)
Contract drilling net of inter-segment revenue	115,183		72,061		213,171		132,915
Oil and natural gas	131,662		91,136		241,496		190,189
Gas gathering and processing	63,894		47,008		120,902		100,742
Elimination of inter-segment revenue	(19,526)		(10,664)		(36,770)		(23,263)
Gas gathering and processing net of inter-segment revenue	44,368		36,344		84,132		77,479
Other	282		5,062		101		10,570
Total revenues	291,495		204,603		538,900		411,153
Contract drilling	31,727		9,075		59,574		15,243
Oil and natural gas	53,695		41,000		92,480		89,683
Gas gathering and processing	3,742		3,424		10,678		7,892
Total operating income	89,164	[1]	53,499	[1]	162,732	[1]	112,818	[1]
General and administrative expense	(7,496)		(6,456)		(14,388)		(12,735)
Interest expense, net	(673)		0		(727)		0
Other income, net	282		5,062		101		10,570
Income before income taxes	$ 81,277		$ 52,105		$ 147,718		$ 110,653

[1] (1) 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.