Condensed Consolidated Statements of Cash Flows - Unaudited - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Statement of Cash Flows [Abstract]
Net (loss) income	$ (210,860)	$ 35,587
Adjustments to reconcile net (loss) income to net cash provided by operating activities
Unrealized (gain) loss on derivatives	(3,762)	39,562
Depletion, depreciation and amortization	184,057	156,999
Accretion of asset retirement obligations	971	834
Full-cost ceiling impairment	324,001	0
Stock-based compensation expense	7,080	9,076
Deferred income tax (benefit) provision	(69,866)	11,845
Amortization of debt issuance cost	1,399	1,189
Net loss on asset sales and impairment	2,632	368
Changes in operating assets and liabilities
Accounts receivable	46,628	(378)
Lease and well equipment inventory	(868)	(3,456)
Prepaid expenses and other current assets	(1,610)	(4,834)
Other long-term assets	1,806	(415)
Accounts payable, accrued liabilities and other current liabilities	(52,351)	(48,746)
Royalties payable	(24,198)	1,353
Advances from joint interest owners	5,094	(6,243)
Other long-term liabilities	232	1,756
Net cash provided by operating activities	210,385	194,497
Investing activities
Oil and natural gas properties capital expenditures	(335,098)	(349,915)
Midstream capital expenditures	(123,338)	(64,106)
Expenditures for other property and equipment	(1,381)	(2,206)
Proceeds from sale of assets	1,056	21,533
Net cash used in investing activities	(458,761)	(394,694)
Financing activities
Borrowings under Credit Agreement	130,000	165,000
Borrowings under San Mateo Credit Facility	32,000	20,000
Cost to amend Credit Agreement	(660)	(415)
Proceeds from stock options exercised	45	3,298
Contributions related to formation of San Mateo I	14,700	14,700
Contributions from non-controlling interest owners of less-than-wholly-owned subsidiaries	67,172	19,831
Distributions to non-controlling interest owners of less-than-wholly-owned subsidiaries	(22,050)	(17,640)
Taxes paid related to net share settlement of stock-based compensation	(1,493)	(3,309)
Other	7,042	(490)
Net cash provided by financing activities	226,756	200,975
(Decrease) increase in cash and restricted cash	(21,620)	778
Cash and restricted cash at beginning of period	65,128	83,984
Cash and restricted cash at end of period	$ 43,508	$ 84,762