Industry Segment Information (Industry Segment Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018		Mar. 31, 2017
Revenues:
Oil and natural gas	$ 103,099		$ 87,598
Contract drilling	45,989		37,185
Gas gathering and processing	56,044		50,941
Total revenues	205,132		175,724
Operating costs:
Oil and natural gas	35,962		29,204
Contract drilling	31,667		29,227
Gas gathering and processing	41,604		37,704
Total operating costs	109,233		96,135
Depreciation, depletion, and amortization	57,066		46,932
Total expenses	166,299		143,067
General and administrative expense	(10,762)		(8,954)
Gain on disposition of assets	161		824
Gain (loss) on derivatives	(6,762)		14,731
Interest expense, net	(10,004)		(9,396)
Other	6		3
Income (loss) before income taxes	11,472		29,865
Oil and Natural Gas [Member]
Revenues:
Oil and natural gas	103,099	[1]	87,598
Contract drilling	0	[1]	0
Gas gathering and processing	0	[1]	0
Total revenues	103,099	[1]	87,598
Operating costs:
Oil and natural gas	37,152		30,326
Contract drilling	0		0
Gas gathering and processing	0		0
Total operating costs	37,152		30,326
Depreciation, depletion, and amortization	30,783		21,526
Total expenses	67,935		51,852
Total operating income (loss)	35,164	[2]	35,746	[3]
General and administrative expense	0		0
Gain on disposition of assets	71		9
Gain (loss) on derivatives	0		0
Interest expense, net	0		0
Other	0		0
Income (loss) before income taxes	35,235		35,755
Drilling [Member]
Revenues:
Oil and natural gas	0	[1]	0
Contract drilling	50,710	[1]	37,185
Gas gathering and processing	0	[1]	0
Total revenues	50,710	[1]	37,185
Operating costs:
Oil and natural gas	0		0
Contract drilling	35,954		29,227
Gas gathering and processing	0		0
Total operating costs	35,954		29,227
Depreciation, depletion, and amortization	13,312		12,847
Total expenses	49,266		42,074
Total operating income (loss)	1,444	[2]	(4,889)	[3]
General and administrative expense	0		0
Gain on disposition of assets	26		7
Gain (loss) on derivatives	0		0
Interest expense, net	0		0
Other	0		0
Income (loss) before income taxes	1,470		(4,882)
Mid-Stream [Member]
Revenues:
Oil and natural gas	0	[1]	0
Contract drilling	0	[1]	0
Gas gathering and processing	74,650	[1]	66,464
Total revenues	74,650	[1]	66,464
Operating costs:
Oil and natural gas	0		0
Contract drilling	0		0
Gas gathering and processing	59,020		52,105
Total operating costs	59,020		52,105
Depreciation, depletion, and amortization	11,053		10,818
Total expenses	70,073		62,923
Total operating income (loss)	4,577	[2]	3,541	[3]
General and administrative expense	0		0
Gain on disposition of assets	34		0
Gain (loss) on derivatives	0		0
Interest expense, net	0		0
Other	0		0
Income (loss) before income taxes	4,611		3,541
Other Segments [Member]
Revenues:
Oil and natural gas	0	[1]	0
Contract drilling	0	[1]	0
Gas gathering and processing	0	[1]	0
Total revenues	0	[1]	0
Operating costs:
Oil and natural gas	0		0
Contract drilling	0		0
Gas gathering and processing	0		0
Total operating costs	0		0
Depreciation, depletion, and amortization	1,918		1,741
Total expenses	1,918		1,741
Total operating income (loss)	(1,918)	[2]	(1,741)	[3]
General and administrative expense	(10,762)		(8,954)
Gain on disposition of assets	30		808
Gain (loss) on derivatives	(6,762)		14,731
Interest expense, net	(10,004)		(9,396)
Other	6		3
Income (loss) before income taxes	(29,410)		(4,549)
Eliminations [Member]
Revenues:
Oil and natural gas	0		0
Contract drilling	(4,721)		0
Gas gathering and processing	(18,606)		(15,523)
Total revenues	(23,327)		(15,523)
Operating costs:
Oil and natural gas	(1,190)		(1,122)
Contract drilling	(4,287)		0
Gas gathering and processing	(17,416)		(14,401)
Total operating costs	(22,893)		(15,523)
Depreciation, depletion, and amortization	0		0
Total expenses	(22,893)		(15,523)
Total operating income (loss)	(434)	[2]	0	[3]
General and administrative expense	0		0
Gain on disposition of assets	0		0
Gain (loss) on derivatives	0		0
Interest expense, net	0		0
Other	0		0
Income (loss) before income taxes	$ (434)		$ 0

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

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