Industry Segment Information (Industry Segment Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Revenues:
Oil and natural gas	$ 106,069		$ 188,207
Contract drilling	104,938		124,258
Elimination of inter-segment revenue	(9,861)		(17,658)
Contract drilling net of inter-segment revenue	95,077		106,600
Gas gathering and processing	73,804		120,360
Elimination of inter-segment revenue	(19,851)		(27,179)
Gas gathering and processing net of inter-segment revenue	53,953		93,181
Total revenues	255,099		387,988
Operating income (loss):
Oil and natural gas	(416,853)		88,112
Contract drilling	28,318		24,401
Gas gathering and processing	(916)		2,630
Total operating income (loss)	(389,451)	[1]	115,143	[1]
General and administrative	(9,370)		(9,637)
Gain on disposition of assets	545		9,426
Gain (loss) on derivatives not designated as hedges	6,586		(18,366)
Interest expense, net	(7,240)		(3,790)
Other	(2)		120
Income (loss) before income taxes	$ (398,932)		$ 92,896

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