Segment Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 segment		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting [Abstract]
Number of reportable operating segments	2
Segment Information
Revenues	$ 423,052		$ 426,428		$ 331,631
Depreciation, depletion and amortization	148,631	[1]	115,235	[1]	113,053	[1]
Other operating expenses	194,628	[2]	179,388	[2]	140,634	[2]
Interest expense	38,664		32,919		24,402
Other (income) expense	(15,982)		(47,079)		(4,030)
Income (loss) before income taxes	57,111		145,965		57,572
Income tax (expense) benefit	(22,008)		(52,142)		(20,634)
NET INCOME (LOSS)	35,103		93,823		36,938
Total assets	1,574,584		1,226,271		890,917
Additions to property and equipment	526,521		413,013		285,655
Oil and Gas
Segment Information
Revenues	407,194		422,368		331,631
Depreciation, depletion and amortization	140,967	[1]	112,863	[1]	111,353	[1]
Other operating expenses	176,922	[2]	174,027	[2]	139,212	[2]
Interest expense	38,664		32,919		24,397
Other (income) expense	(15,979)		(33,280)		(4,030)
Income (loss) before income taxes	66,620		135,839		60,699
Income tax (expense) benefit	(25,473)		(48,648)		(21,228)
NET INCOME (LOSS)	41,147		87,191		39,471
Total assets	1,535,544		1,178,725		854,621
Additions to property and equipment	510,924		395,292		270,108
Contract Drilling
Segment Information
Revenues	57,218		52,716		35,269
Depreciation, depletion and amortization	14,442	[1]	12,214	[1]	10,044	[1]
Other operating expenses	52,678	[2]	44,318	[2]	26,916	[2]
Interest expense	0		0		5
Other (income) expense	(3)		(13,799)		0
Income (loss) before income taxes	(9,899)		9,983		(1,696)
Income tax (expense) benefit	3,465		(3,494)		594
NET INCOME (LOSS)	(6,434)		6,489		(1,102)
Total assets	64,045		62,846		48,414
Additions to property and equipment	15,207		17,578		16,978
Intercompany Eliminations
Segment Information
Revenues	(41,360)		(48,656)		(35,269)
Depreciation, depletion and amortization	(6,778)	[1]	(9,842)	[1]	(8,344)	[1]
Other operating expenses	(34,972)	[2]	(38,957)	[2]	(25,494)	[2]
Interest expense	0		0		0
Other (income) expense	0		0		0
Income (loss) before income taxes	390		143		(1,431)
Income tax (expense) benefit	0		0		0
NET INCOME (LOSS)	390		143		(1,431)
Total assets	(25,005)		(15,300)		(12,118)
Additions to property and equipment	$ 390		$ 143		$ (1,431)

[1] Includes impairment of property and equipment.

[2] Includes the following expenses: production, exploration, midstream services, drilling rig services, accretion of asset retirement obligations, general and administrative, and other operating expenses.