Industry Segment Information (Industry Segment Information) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Revenues:
Oil and natural gas	$ 111,623		$ 85,470	$ 317,040		$ 256,241
Contract drilling	50,612		51,619	143,527		128,059
Gas gathering and processing	57,823		51,399	167,926		150,493
Total revenues	220,058		188,488	628,493		534,793
Operating costs:
Oil and natural gas	32,139		33,911	100,519		95,873
Contract drilling	32,032		34,747	95,593		91,213
Gas gathering and processing	43,134		38,116	124,441		111,862
Total operating costs	107,305		106,774	320,553		298,948
Depreciation, depletion, and amortization	63,537		54,533	178,976		151,545
Total expenses	170,842		161,307	499,529		450,493
General and administrative	9,278		9,235	28,752		26,902
(Gain) loss on disposition of assets	(253)		(81)	(575)		(1,153)
Income (loss) from operations	40,191		18,027	100,787		58,551
Gain (loss) on derivatives	(4,385)		(2,614)	(25,608)		21,019
Interest, net	(7,945)		(9,944)	(25,678)		(28,807)
Other	6		5	17		14
Income (loss) before income taxes	27,867		5,474	49,518		50,777
Oil and Natural Gas [Member]
Revenues:
Oil and natural gas	111,623	[1]	85,470	317,040	[2]	256,241
Contract drilling	0	[1]	0	0	[2]	0
Gas gathering and processing	0	[1]	0	0	[2]	0
Total revenues	111,623	[1]	85,470	317,040	[2]	256,241
Operating costs:
Oil and natural gas	33,400		35,082	104,234		99,349
Contract drilling	0		0	0		0
Gas gathering and processing	0		0	0		0
Total operating costs	33,400		35,082	104,234		99,349
Depreciation, depletion, and amortization	35,460		26,460	97,797		71,544
Total expenses	68,860		61,542	202,031		170,893
General and administrative	0		0	0		0
(Gain) loss on disposition of assets	(7)		1	(136)		(176)
Income (loss) from operations	42,770		23,927	115,145		85,524
Gain (loss) on derivatives	0		0	0		0
Interest, net	0		0	0		0
Other	0		0	0		0
Income (loss) before income taxes	42,770		23,927	115,145		85,524
Drilling [Member]
Revenues:
Oil and natural gas	0	[1]	0	0	[2]	0
Contract drilling	58,012	[1]	55,588	161,489	[2]	137,617
Gas gathering and processing	0	[1]	0	0	[2]	0
Total revenues	58,012	[1]	55,588	161,489	[2]	137,617
Operating costs:
Oil and natural gas	0		0	0		0
Contract drilling	38,246		38,115	111,121		99,794
Gas gathering and processing	0		0	0		0
Total operating costs	38,246		38,115	111,121		99,794
Depreciation, depletion, and amortization	14,889		15,280	41,927		41,896
Total expenses	53,135		53,395	153,048		141,690
General and administrative	0		0	0		0
(Gain) loss on disposition of assets	(230)		(68)	(314)		(106)
Income (loss) from operations	5,107		2,261	8,755		(3,967)
Gain (loss) on derivatives	0		0	0		0
Interest, net	0		0	0		0
Other	0		0	0		0
Income (loss) before income taxes	5,107		2,261	8,755		(3,967)
Mid-Stream [Member]
Revenues:
Oil and natural gas	0	[1]	0	0	[2]	0
Contract drilling	0	[1]	0	0	[2]	0
Gas gathering and processing	82,882	[1]	69,057	232,938	[2]	198,632
Total revenues	82,882	[1]	69,057	232,938	[2]	198,632
Operating costs:
Oil and natural gas	0		0	0		0
Contract drilling	0		0	0		0
Gas gathering and processing	66,932		54,602	185,738		156,525
Total operating costs	66,932		54,602	185,738		156,525
Depreciation, depletion, and amortization	11,265		10,880	33,493		32,547
Total expenses	78,197		65,482	219,231		189,072
General and administrative	0		0	0		0
(Gain) loss on disposition of assets	(16)		(14)	(95)		(58)
Income (loss) from operations	4,701		3,589	13,802		9,618
Gain (loss) on derivatives	0		0	0		0
Interest, net	(381)		0	(834)		0
Other	0		0	0		0
Income (loss) before income taxes	4,320		3,589	12,968		9,618
Other Segments [Member]
Revenues:
Oil and natural gas	0	[1]	0	0	[2]	0
Contract drilling	0	[1]	0	0	[2]	0
Gas gathering and processing	0	[1]	0	0	[2]	0
Total revenues	0	[1]	0	0	[2]	0
Operating costs:
Oil and natural gas	0		0	0		0
Contract drilling	0		0	0		0
Gas gathering and processing	3,808		0	7,384		0
Total operating costs	3,808		0	7,384		0
Depreciation, depletion, and amortization	1,923		1,913	5,759		5,558
Total expenses	5,731		1,913	13,143		5,558
General and administrative	9,278		9,235	28,752		26,902
(Gain) loss on disposition of assets	0		0	(30)		(813)
Income (loss) from operations	(15,009)		(11,148)	(41,865)		(31,647)
Gain (loss) on derivatives	(4,385)		(2,614)	(25,608)		21,019
Interest, net	(7,564)		(9,944)	(24,844)		(28,807)
Other	3,814		5	7,401		14
Income (loss) before income taxes	(23,144)		(23,701)	(84,916)		(39,421)
Eliminations [Member]
Revenues:
Oil and natural gas	0		0	0		0
Contract drilling	(7,400)		(3,969)	(17,962)		(9,558)
Gas gathering and processing	(25,059)		(17,658)	(65,012)		(48,139)
Total revenues	(32,459)		(21,627)	(82,974)		(57,697)
Operating costs:
Oil and natural gas	(1,261)		(1,171)	(3,715)		(3,476)
Contract drilling	(6,214)		(3,368)	(15,528)		(8,581)
Gas gathering and processing	(27,606)		(16,486)	(68,681)		(44,663)
Total operating costs	(35,081)		(21,025)	(87,924)		(56,720)
Depreciation, depletion, and amortization	0		0	0		0
Total expenses	(35,081)		(21,025)	(87,924)		(56,720)
General and administrative	0		0	0		0
(Gain) loss on disposition of assets	0		0	0		0
Income (loss) from operations	2,622		(602)	4,950		(977)
Gain (loss) on derivatives	0		0	0		0
Interest, net	0		0	0		0
Other	(3,808)		0	(7,384)		0
Income (loss) before income taxes	$ (1,186)		$ (602)	$ (2,434)		$ (977)

[1] The revenues for oil and natural gas occur at a point in time. The revenues for contract drilling and gas gathering and processing occur over time.

[2] The revenues for oil and natural gas occur at a point in time. The revenues for contract drilling and gas gathering and processing occur over time.