Industry Segment Information (Industry Segment Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Revenues:
Oil and natural gas	$ 164,799		$ 131,166		$ 318,408		$ 266,931
Contract drilling	118,660		160,925		238,013		313,384
Elimination of inter-segment revenue	(13,655)		(14,053)		(25,480)		(25,606)
Contract drilling net of inter-segment revenue	105,005		146,872		212,533		287,778
Gas gathering and processing	92,910		65,901		173,066		140,156
Elimination of inter-segment revenue	(22,293)		(16,154)		(45,054)		(33,114)
Gas gathering and processing net of inter-segment revenue	70,617		49,747		128,012		107,042
Total revenues	340,421		327,785		658,953		661,751
Operating income (loss):
Oil and natural gas	(64,470)		75,140	[1]	(123,058)		27,181	[1]
Contract drilling	(23,507)		(50,815)		(47,773)		(94,220)
Gas gathering and processing	(2,846)		(2,072)		(3,675)		(6,620)
Total operating income (loss) (1)	90,823	[2]	(22,253)	[2]	174,506	[2]	73,659	[2]
General and administrative	(9,679)		(8,376)		(18,352)		(15,380)
Gain on disposition of assets	3,483		651		3,399		1,239
Gain (loss) on derivatives not designated as hedges and hedge ineffectiveness, net	16,344		1,387		10,420		(606)
Interest expense, net	(4,591)		(2,542)		(8,152)		(4,368)
Other	(91)		69		(157)		(64)
Income (loss) before income taxes	$ 96,289		$ (31,064)		$ 161,664		$ 54,480

[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 is total operating revenues less operating expenses, depreciation, depletion, amortization, and impairment and does not include non-operating revenues, general corporate expenses, gain on disposition of assets, interest expense, or income taxes.