Industry Segment Information (Industry Segment Information) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues:
Oil and natural gas		$ 107,256	$ 198,498	$ 213,325	$ 386,705
Contract drilling		60,813	135,782	165,751	260,040
Elimination of inter-segment revenue		(5,798)	(21,504)	(15,659)	(39,162)
Contract drilling net of inter-segment revenue		55,015	114,278	150,092	220,878
Gas gathering and processing		69,163	116,354	142,967	236,714
Elimination of inter-segment revenue		(16,987)	(23,699)	(36,838)	(50,878)
Gas gathering and processing net of inter-segment revenue		52,176	92,655	106,129	185,836
Total revenues		214,447	405,431	469,546	793,419
Operating income (loss):
Oil and natural gas		(417,353)	82,530	(834,206)	170,642
Contract drilling		(3,049)	27,545	25,269	51,946
Gas gathering and processing		736	3,898	(180)	6,528
Total operating income (loss)	[1]	(419,666)	113,973	(809,117)	229,116
General and administrative		(9,624)	(10,600)	(18,994)	(20,237)
Gain on disposition of assets		415	195	960	9,621
Gain (loss) on derivatives not designated as hedges		(1,919)	(10,709)	4,667	(29,075)
Interest expense, net		(7,956)	(4,131)	(15,196)	(7,921)
Other		24	(49)	22	71
Income (loss) before income taxes		$ (438,726)	$ 88,679	$ (837,658)	$ 181,575

[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.