Supplemental Condensed Consolidated Financial Information (Condensed Consolidating Statements of Cash Flow) (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities	$ 29,807	$ 44,956	$ 269,396
INVESTING ACTIVITIES:
Capital expeditures	(4,057)	(25,775)	(406,665)
Producing property and other oil and natural gas acquisitions	0	(382)	(3,653)
Other acquisitions	0	0	16,109
Proceeds from disposition of property and equipment	1,799	6,018	31,864
Net cash provided by (used in) investing activities	(2,258)	(20,139)	(394,563)
FINANCING ACTIVITIES:
Borrowings under line of credit	0	87,400	493,500
Payments under line of credit	(49,000)	(64,100)	(368,800)
Intercompany borrowings (advances), net		0	0
Net payments on finance leases	(1,406)	(2,757)	(4,001)
Employee taxes paid by withholding shares	0	(43)	(4,158)
Distributions to non-controlling interest	0	0	(918)
Proceeds from investments of non-contolling interests	0	0	0
Transaction costs associated with sale of non-controlling interest	0	0	0
Bank overdrafts	2,631	(8,733)	3,663
Net cash provided by (used in) financing activities	(47,775)	7,552	119,286
Net increase (decrease) in cash and cash equivalents	(20,226)	32,369	(5,881)
Cash, restricted cash, cash equivalents, beginning of year	32,940	571	6,452
Cash, restricted cash, cash equivalents, end of year	12,714	32,940	571
DIP financing costs	0	(990)	0
Exit facility financing costs	0	(3,225)	0
Consolidating Adjustments
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		136,858	12,338
INVESTING ACTIVITIES:
Capital expeditures		0	0
Producing property and other oil and natural gas acquisitions		0	0
Other acquisitions			0
Proceeds from disposition of property and equipment		0	0
Net cash provided by (used in) investing activities		0	0
FINANCING ACTIVITIES:
Borrowings under line of credit		0	0
Payments under line of credit		0	0
Intercompany borrowings (advances), net		(136,858)	(12,338)
Net payments on finance leases		0	0
Employee taxes paid by withholding shares		0	0
Distributions to non-controlling interest			0
Bank overdrafts		0	0
Net cash provided by (used in) financing activities		(136,858)	(12,338)
Net increase (decrease) in cash and cash equivalents		0	0
Cash, restricted cash, cash equivalents, beginning of year	0	0
Cash, restricted cash, cash equivalents, end of year		0	0
DIP financing costs		0
Exit facility financing costs		0
Parent
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		(207,593)	(9,681)
INVESTING ACTIVITIES:
Capital expeditures		(986)	65
Producing property and other oil and natural gas acquisitions		0	0
Other acquisitions			0
Proceeds from disposition of property and equipment		1,169	11
Net cash provided by (used in) investing activities		183	76
FINANCING ACTIVITIES:
Borrowings under line of credit		55,300	400,600
Payments under line of credit		(31,500)	(292,400)
Intercompany borrowings (advances), net		210,398	(97,455)
Net payments on finance leases		0	0
Employee taxes paid by withholding shares		(43)	(4,158)
Distributions to non-controlling interest			919
Bank overdrafts		(7,269)	2,199
Net cash provided by (used in) financing activities		222,671	9,705
Net increase (decrease) in cash and cash equivalents		15,261	100
Cash, restricted cash, cash equivalents, beginning of year	15,764	503
Cash, restricted cash, cash equivalents, end of year		15,764	503
Combined Guarantor Subsidiaries
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		82,769	217,883
INVESTING ACTIVITIES:
Capital expeditures		(14,585)	(355,258)
Producing property and other oil and natural gas acquisitions		(382)	(3,653)
Other acquisitions			0
Proceeds from disposition of property and equipment		4,772	31,153
Net cash provided by (used in) investing activities		(10,195)	(327,758)
FINANCING ACTIVITIES:
Borrowings under line of credit		0	0
Payments under line of credit		0	0
Intercompany borrowings (advances), net		(72,642)	109,735
Net payments on finance leases		0	0
Employee taxes paid by withholding shares		0	0
Distributions to non-controlling interest			0
Bank overdrafts		0	0
Net cash provided by (used in) financing activities		(72,642)	109,735
Net increase (decrease) in cash and cash equivalents		(68)	(140)
Cash, restricted cash, cash equivalents, beginning of year	0	68
Cash, restricted cash, cash equivalents, end of year		0	68
DIP financing costs		0
Exit facility financing costs		0
Combined Non-Guarantor Subsidiaries
OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		32,922	48,856
INVESTING ACTIVITIES:
Capital expeditures		(10,204)	(51,472)
Producing property and other oil and natural gas acquisitions		0	0
Other acquisitions			16,109
Proceeds from disposition of property and equipment		77	700
Net cash provided by (used in) investing activities		(10,127)	(66,881)
FINANCING ACTIVITIES:
Borrowings under line of credit		32,100	92,900
Payments under line of credit		(32,600)	(76,400)
Intercompany borrowings (advances), net		(898)	58
Net payments on finance leases		(2,757)	(4,001)
Employee taxes paid by withholding shares		0	0
Distributions to non-controlling interest			(1,837)
Bank overdrafts		(1,464)	1,464
Net cash provided by (used in) financing activities		(5,619)	12,184
Net increase (decrease) in cash and cash equivalents		17,176	(5,841)
Cash, restricted cash, cash equivalents, beginning of year	$ 17,176	0
Cash, restricted cash, cash equivalents, end of year		17,176	$ 0
DIP financing costs		0
Exit facility financing costs		0
Parent Company [Member]
FINANCING ACTIVITIES:
DIP financing costs		(990)
Exit facility financing costs		$ (3,225)