Industry Segment Information (Revenue From Different Segments) (Details) (USD $)	1 Months Ended	3 Months Ended								12 Months Ended
	Mar. 31, 2009	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Industry Segment Information [Abstract]
Contract drilling										$ 536,872,000		$ 356,527,000		$ 251,364,000
Elimination of inter-segment revenue										(52,221,000)		(40,143,000)		(15,049,000)
Contract drilling net of inter-segment revenue										484,651,000		316,384,000		236,315,000
Oil and natural gas										516,316,000		400,807,000		357,879,000
Gas gathering and processing										284,248,000		201,320,000		142,491,000
Elimination of inter-segment revenue										(76,010,000)		(46,804,000)		(33,863,000)
Gas gathering and processing net of inter-segment revenue										208,238,000		154,516,000		108,628,000
Other, net										(834,000)		10,138,000		7,076,000
Total revenues		345,626,000	323,845,000	291,495,000	247,405,000	252,576,000	218,116,000	204,603,000	206,550,000	1,208,371,000		881,845,000		709,898,000
Contract drilling										135,085,000		59,601,000		50,909,000
Oil and natural gas										201,695,000		176,649,000		(125,777,000)	[1]
Gas gathering and processing										17,278,000		16,985,000		4,616,000
Total operating income (loss)										354,058,000	[2]	253,235,000	[2]	(70,252,000)	[2]
General and administrative expense										(30,055,000)		(26,152,000)		(24,011,000)
Interest expense, net										(4,167,000)		0		(539,000)
Other income (loss), net										(834,000)		10,138,000		7,076,000
Income (loss) before income taxes										319,002,000		237,221,000		(87,726,000)
Contract drilling										1,118,666,000		998,658,000		951,702,000
Oil and natural gas										1,820,492,000		1,441,797,000		1,068,970,000
Gas gathering and processing		247,763,000				176,596,000				247,763,000		176,596,000		163,625,000
Total identifiable assets										3,186,921,000	[3]	2,617,051,000	[3]	2,184,297,000	[3]
Corporate assets										69,799,000		52,189,000		44,102,000
Total assets		3,256,720,000				2,669,240,000				3,256,720,000		2,669,240,000		2,228,399,000
Contract drilling										162,208,000		118,806,000		67,686,000
Oil and natural gas										580,055,000		463,870,000		230,550,000
Gas gathering and processing										79,355,000		29,815,000		9,899,000
Other										10,791,000		6,417,000		474,000
Total capital expenditures										832,409,000		618,908,000		308,609,000
Contract drilling										79,667,000		69,970,000		45,326,000
Depreciation, depletion and amortization										183,350,000		118,793,000		114,681,000
Impairment of oil and natural gas properties										0		0		281,241,000	[1]
Gas gathering and processing										16,101,000		15,385,000		16,104,000
Other										1,333,000		976,000		1,055,000
Total depreciation, depletion, amortization and impairment										280,451,000		205,124,000		458,407,000
Non-cash write down of our oil and natural gas properties	281,200,000
Non-cash write down of our oil and natural gas properties net of tax	$ 175,100,000

[1] In March 2009, we incurred a $281.2 million pre-tax ($175.1 million net of tax) non-cash write down of our oil and natural gas properties due to low commodity prices existing at the end of the first quarter 2009.

[2] 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.

[3] Identifiable assets are those used in Unit's operations in each industry segment. Corporate assets are principally cash and cash equivalents, short-term investments, corporate leasehold improvements, furniture and equipment.