Supplemental Condensed Consolidated Financial Information (Condensed Consolidating Statements of Cash Flows (Unaudited)) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities	$ 219,450	$ 241,482
INVESTING ACTIVITIES:
Capital expenditures	(364,954)	(304,054)
Producing properties and other acquisitions	(3,345)	(769)
Proceeds from disposition of assets	10,506	25,316
Net cash provided by (used in) investing activities	(357,793)	(279,507)
FINANCING ACTIVITIES:
Borrowings under credit agreement	392,200	71,200
Payments under credit agreement	(254,000)	(249,200)
Intercompany borrowings (advances), net	0	0
Payments on finance leases	(2,984)	(2,869)
Employee taxes paid by withholding shares	(4,080)	(4,947)
Proceeds from investments of non-controlling interests	0	300,000
Transaction costs associated with non-controlling interests	0	(2,303)
Distributions to non-controlling interest	(918)	0
Bank overdrafts	2,285	17,000
Net cash provided by (used in) financing activities	132,503	128,881
Net increase (decrease) in cash and cash equivalents	(5,840)	90,856
Cash and cash equivalents, beginning of period	6,452	701
Cash and cash equivalents, end of period	612	91,557
Consolidating Adjustments [Member]
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities	(34)	128,080
INVESTING ACTIVITIES:
Capital expenditures	0	0
Producing properties and other acquisitions	0	0
Proceeds from disposition of assets	0	0
Net cash provided by (used in) investing activities	0	0
FINANCING ACTIVITIES:
Borrowings under credit agreement	0	0
Payments under credit agreement	0	0
Intercompany borrowings (advances), net	34	(128,080)
Payments on finance leases	0	0
Employee taxes paid by withholding shares	0	0
Proceeds from investments of non-controlling interests		0
Transaction costs associated with non-controlling interests		0
Distributions to non-controlling interest	0
Bank overdrafts	0	0
Net cash provided by (used in) financing activities	34	(128,080)
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Parent [Member]
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities	11,054	(98,489)
INVESTING ACTIVITIES:
Capital expenditures	168	22
Producing properties and other acquisitions	0	0
Proceeds from disposition of assets	11	30
Net cash provided by (used in) investing activities	179	52
FINANCING ACTIVITIES:
Borrowings under credit agreement	332,300	69,200
Payments under credit agreement	(198,200)	(247,200)
Intercompany borrowings (advances), net	(143,692)	248,343
Payments on finance leases	0	0
Employee taxes paid by withholding shares	(4,080)	(4,947)
Proceeds from investments of non-controlling interests		102,958
Transaction costs associated with non-controlling interests		(2,303)
Distributions to non-controlling interest	919
Bank overdrafts	1,622	14,143
Net cash provided by (used in) financing activities	(11,131)	180,194
Net increase (decrease) in cash and cash equivalents	102	81,757
Cash and cash equivalents, beginning of period	403	510
Cash and cash equivalents, end of period	505	82,267
Combined Guarantor Subsidiaries [Member]
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities	169,838	215,350
INVESTING ACTIVITIES:
Capital expenditures	(321,840)	(275,434)
Producing properties and other acquisitions	(3,345)	(769)
Proceeds from disposition of assets	10,376	25,199
Net cash provided by (used in) investing activities	(314,809)	(251,004)
FINANCING ACTIVITIES:
Borrowings under credit agreement	0	0
Payments under credit agreement	0	0
Intercompany borrowings (advances), net	144,867	35,714
Payments on finance leases	0	0
Employee taxes paid by withholding shares	0	0
Proceeds from investments of non-controlling interests		0
Transaction costs associated with non-controlling interests		0
Distributions to non-controlling interest	0
Bank overdrafts	0	0
Net cash provided by (used in) financing activities	144,867	35,714
Net increase (decrease) in cash and cash equivalents	(104)	60
Cash and cash equivalents, beginning of period	208	191
Cash and cash equivalents, end of period	104	251
Combined Non-Guarantor Subsidiaries [Member]
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities	38,592	(3,459)
INVESTING ACTIVITIES:
Capital expenditures	(43,282)	(28,642)
Producing properties and other acquisitions	0	0
Proceeds from disposition of assets	119	87
Net cash provided by (used in) investing activities	(43,163)	(28,555)
FINANCING ACTIVITIES:
Borrowings under credit agreement	59,900	2,000
Payments under credit agreement	(55,800)	(2,000)
Intercompany borrowings (advances), net	(1,209)	(155,977)
Payments on finance leases	(2,984)	(2,869)
Employee taxes paid by withholding shares	0	0
Proceeds from investments of non-controlling interests		197,042
Transaction costs associated with non-controlling interests		0
Distributions to non-controlling interest	(1,837)
Bank overdrafts	663	2,857
Net cash provided by (used in) financing activities	(1,267)	41,053
Net increase (decrease) in cash and cash equivalents	(5,838)	9,039
Cash and cash equivalents, beginning of period	5,841	0
Cash and cash equivalents, end of period	$ 3	$ 9,039