Industry Segment Information (Revenue From Different Segments) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting [Abstract]
Contract drilling									$ 579,368,000		$ 536,872,000		$ 356,527,000
Elimination of inter-segment revenue									(49,649,000)		(52,221,000)		(40,143,000)
Contract drilling net of inter-segment revenue									529,719,000		484,651,000		316,384,000
Oil and natural gas									567,944,000		514,614,000		399,771,000
Gas gathering and processing									290,773,000		284,248,000		201,320,000
Elimination of inter-segment revenue									(73,313,000)		(76,010,000)		(46,804,000)
Gas gathering and processing									217,460,000		208,238,000		154,516,000
Total revenues	331,582,000	321,790,000	327,785,000	333,966,000	347,341,000	322,237,000	287,829,000	250,096,000	1,315,123,000		1,207,503,000		870,671,000
Contract drilling									159,188,000		135,085,000		59,601,000
Oil and natural gas									(77,221,000)		199,993,000		175,613,000
Gas gathering and processing									5,780,000		17,278,000		16,985,000
Total operating income									87,747,000	[1]	352,356,000	[1]	252,199,000	[1]
General and administrative expense									(33,086,000)		(30,055,000)		(26,152,000)
Interest expense, net									(14,137,000)		(4,167,000)		0
Gain (loss) on derivatives not desgignated as hedges and hedge ineffectiveness, net									(1,243,000)		1,702,000		1,036,000
Other Income (loss), net									121,000		(834,000)		10,138,000
Income before income taxes									39,402,000		319,002,000		237,221,000
Contract drilling									1,079,736,000		1,118,666,000		998,658,000
Oil and natural gas									2,214,029,000		1,820,492,000		1,441,797,000
Gas gathering and processing	413,708,000				247,763,000				413,708,000		247,763,000		176,596,000
Total identifiable assets									3,707,473,000	[2]	3,186,921,000	[2]	2,617,051,000	[2]
Corporate assets									53,647,000		69,799,000		52,189,000
Total assets	3,761,120,000				3,256,720,000				3,761,120,000		3,256,720,000		2,669,240,000
Contract drilling									77,520,000		162,208,000		118,806,000
Oil and natural gas									1,128,349,000		580,055,000		463,870,000
Gas gathering and processing									183,162,000		79,355,000		29,815,000
Other									28,071,000		10,791,000		6,417,000
Total capital expenditures									1,417,102,000		832,409,000		618,908,000
Contract drilling									81,007,000		79,667,000		69,970,000
Oil and Gas depreciation, depletion and amortization									211,347,000		183,350,000		118,793,000
Impairment of oil and natural gas properties									283,606,000	[3]	0		0
Gas gathering and processing									24,388,000	[4]	16,101,000		15,385,000
Other									2,279,000		1,333,000		976,000
Total depreciation, depletion, amortization and impairment									602,627,000		280,451,000		205,124,000
Non-cash write down of our oil and natural gas properties	167,700,000		115,900,000
Non-cash write down of our oil and natural gas properties net of tax	104,400,000		72,100,000
Impairment of Long-Lived Assets Held-for-use	$ 1,200,000								$ 1,200,000

[1] Operating income is total operating revenues less operating expenses, depreciation, depletion, amortization, and impairment and does not include general corporate expenses, gain (loss) on non-designated hedges and hedge ineffectiveness, interest expense, other income (loss), or income taxes.

[2] 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.

[3] In June 2012 and December 2012, due to low 12-month average commodity prices, we incurred non-cash ceiling test write downs of our oil and natural gas properties of $115.9 million pre-tax ($72.1 million net of tax) and $167.7 million pre-tax ($104.4 million net of tax), respectively.

[4] Depreciation, depletion, amortization, and impairment for gas gathering and processing includes a $1.2 million write down of our Erick system.