Condensed Consolidated Statements of Cash Flows - Unaudited - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Statement of Cash Flows [Abstract]
Current period net (loss) income	$ 89,340	$ 155,676
Adjustments to reconcile net income to net cash provided by operating activities
Unrealized loss on derivatives	29,715	9,492
Depletion, depreciation and amortization	249,497	192,664
Accretion of asset retirement obligations	1,354	1,126
Stock-based compensation expense	13,740	13,787
Prepayment premium on extinguishment of debt	0	31,226
Deferred income tax provision	25,335	0
Amortization of debt issuance cost	1,814	851
Net loss on asset sales and inventory impairment	807	196
Changes in operating assets and liabilities
Accounts receivable	(37,341)	(5,654)
Lease and well equipment inventory	2,307	(15,347)
Prepaid expenses	(5,099)	(502)
Other assets	(291)	0
Accounts payable, accrued liabilities and other current liabilities	(15,540)	20,823
Royalties payable	(586)	5,665
Advances from joint interest owners	(3,159)	9,565
Other long-term liabilities	1,234	(250)
Net cash provided by operating activities	353,127	419,318
Investing activities
Oil and natural gas properties capital expenditures	(536,017)	(1,106,556)
Midstream capital expenditures	(120,792)	(120,669)
Expenditures for other property and equipment	(3,911)	(1,570)
Proceeds from sale of assets	21,671	8,267
Net cash used in investing activities	(639,049)	(1,220,528)
Financing activities
Repayments of borrowings	(10,000)	(45,000)
Borrowings under Credit Agreement	185,000	370,000
Borrowings under San Mateo Credit Facility	40,000	0
Cost to amend credit facilities	(613)	0
Proceeds from issuance of senior unsecured notes	0	750,000
Cost to issue senior unsecured notes	0	(9,531)
Purchase of senior unsecured notes	0	(605,780)
Proceeds from issuance of common stock	0	226,612
Cost to issue equity	0	(146)
Proceeds from stock options exercised	3,300	827
Contributions related to formation of San Mateo I	14,700	14,700
Contributions from non-controlling interest owners of less-than-wholly-owned subsidiaries	42,330	73,500
Distributions to non-controlling interest owners of less-than-wholly-owned subsidiaries	(27,685)	(17,395)
Taxes paid related to net share settlement of stock-based compensation	(3,665)	(6,051)
Cash paid under financing lease obligations	(623)	0
Net cash provided by financing activities	242,744	751,736
Increase in cash and restricted cash	(43,178)	(49,474)
Cash and restricted cash at beginning of period	83,984	102,482
Cash and restricted cash at end of period	$ 40,806	$ 53,008