Industry Segment Information (Industry Segment Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018
Revenues:
Revenues	$ 189,691		$ 205,132
Operating costs:
Operating costs	103,470		109,233
Depreciation, depletion, and amortization	62,126		57,066
Total expenses	165,596		166,299
General and administrative	9,741		10,762
(Gain) loss on disposition of assets	1,615		(161)
Income (loss) from operations	12,739		28,232
Loss on derivatives	(6,932)		(6,762)
Interest, net	(8,538)		(10,004)
Other	5		6
Income (loss) before income taxes	(2,726)		11,472
Oil and Natural Gas [Member]
Revenues:
Revenues	86,095	[1]	103,099	[2]
Operating costs:
Operating costs	34,008		37,152
Depreciation, depletion, and amortization	35,767		30,783
Total expenses	69,775		67,935
General and administrative	0		0
(Gain) loss on disposition of assets	(79)		(71)
Income (loss) from operations	16,399		35,235
Loss on derivatives	0		0
Interest, net	0		0
Other	0		0
Income (loss) before income taxes	16,399		35,235
Drilling [Member]
Revenues:
Revenues	58,199	[1]	50,710	[2]
Operating costs:
Operating costs	37,385		35,954
Depreciation, depletion, and amortization	12,699		13,312
Total expenses	50,084		49,266
General and administrative	0		0
(Gain) loss on disposition of assets	1,746		(26)
Income (loss) from operations	6,369		1,470
Loss on derivatives	0		0
Interest, net	0		0
Other	0		0
Income (loss) before income taxes	6,369		1,470
Mid-Stream [Member]
Revenues:
Revenues	70,509	[1]	74,650	[2]
Operating costs:
Operating costs	56,129		59,020
Depreciation, depletion, and amortization	11,726		11,053
Total expenses	67,855		70,073
General and administrative	0		0
(Gain) loss on disposition of assets	(42)		(34)
Income (loss) from operations	2,696		4,611
Loss on derivatives	0		0
Interest, net	(336)		(149)
Other	0		0
Income (loss) before income taxes	2,360		4,462
Other Segments [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Depreciation, depletion, and amortization	1,934		1,918
Total expenses	1,934		1,918
General and administrative	9,741		10,762
(Gain) loss on disposition of assets	(10)		(30)
Income (loss) from operations	(11,665)		(12,650)
Loss on derivatives	(6,932)		(6,762)
Interest, net	(8,202)		(9,855)
Other	5		6
Income (loss) before income taxes	(26,794)		(29,261)
Eliminations [Member]
Revenues:
Revenues	(25,112)	[1]	(23,327)	[2]
Operating costs:
Operating costs	(24,052)		(22,893)
Depreciation, depletion, and amortization	0		0
Total expenses	(24,052)		(22,893)
General and administrative	0		0
(Gain) loss on disposition of assets	0		0
Income (loss) from operations	(1,060)		(434)
Loss on derivatives	0		0
Interest, net	0		0
Other	0		0
Income (loss) before income taxes	(1,060)		(434)
Oil and natural gas
Revenues:
Revenues	86,095		103,099
Operating costs:
Operating costs	32,714		35,962
Oil and natural gas | Oil and Natural Gas [Member]
Revenues:
Revenues	86,095	[1]	103,099	[2]
Operating costs:
Operating costs	34,008		37,152
Oil and natural gas | Drilling [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Oil and natural gas | Mid-Stream [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Oil and natural gas | Other Segments [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Oil and natural gas | Eliminations [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	(1,294)		(1,190)
Contract drilling
Revenues:
Revenues	51,155		45,989
Operating costs:
Operating costs	31,401		31,667
Contract drilling | Oil and Natural Gas [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Contract drilling | Drilling [Member]
Revenues:
Revenues	58,199	[1]	50,710	[2]
Operating costs:
Operating costs	37,385		35,954
Contract drilling | Mid-Stream [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Contract drilling | Other Segments [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Contract drilling | Eliminations [Member]
Revenues:
Revenues	(7,044)	[1]	(4,721)	[2]
Operating costs:
Operating costs	(5,984)		(4,287)
Gas gathering and processing
Revenues:
Revenues	52,441		56,044
Operating costs:
Operating costs	39,355		41,604
Gas gathering and processing | Oil and Natural Gas [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Gas gathering and processing | Drilling [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Gas gathering and processing | Mid-Stream [Member]
Revenues:
Revenues	70,509	[1]	74,650	[2]
Operating costs:
Operating costs	56,129		59,020
Gas gathering and processing | Other Segments [Member]
Revenues:
Revenues	0	[1]	0	[2]
Operating costs:
Operating costs	0		0
Gas gathering and processing | Eliminations [Member]
Revenues:
Revenues	(18,068)	[1]	(18,606)	[2]
Operating costs:
Operating costs	$ (16,774)		$ (17,416)

[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