Condensed Consolidated Statements of Cash Flows - Unaudited - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net income (loss)	$ 95,566	$ (201,366)
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Unrealized (gain) loss on derivatives	(21,449)	30,261
Depletion, depreciation and amortization	123,066	90,185
Accretion of asset retirement obligations	937	828
Full-cost ceiling impairment	0	158,633
Stock-based compensation expense	12,488	9,138
Amortization of debt issuance cost	103	899
Net gain on asset sales and inventory impairment	(23)	(3,140)
Changes in operating assets and liabilities
Accounts receivable	(50,343)	(7,782)
Lease and well equipment inventory	(1,666)	(669)
Prepaid expenses	(2,224)	(74)
Other assets	217	480
Accounts payable, accrued liabilities and other current liabilities	35,068	9,710
Royalties payable	29,651	5,225
Advances from joint interest owners	2,646	3,147
Income taxes payable	0	(2,848)
Other long-term liabilities	(1,521)	3,835
Net cash provided by operating activities	222,516	96,462
Investing activities
Oil and natural gas properties capital expenditures	(517,270)	(288,175)
Expenditures for other property and equipment	(80,560)	(57,148)
Proceeds from sale of assets	977	5,173
Restricted cash	0	43,098
Restricted cash in less-than-wholly-owned subsidiaries	(9,486)	(544)
Net cash used in investing activities	(606,339)	(297,596)
Financing activities
Borrowings under Credit Agreement	0	65,000
Proceeds from issuance of common stock	0	142,350
Cost to issue equity	0	(830)
Proceeds from stock options exercised	2,920	0
Contributions related to formation of Joint Venture	171,500	0
Contributions from non-controlling interest owners of less-than-wholly-owned subsidiaries	29,400	0
Distributions to non-controlling interest owners of less-than-wholly-owned subsidiaries	(5,635)	0
Taxes paid related to net share settlement of stock-based compensation	(4,415)	(1,552)
Purchase of non-controlling interest of less-than-wholly-owned subsidiary	(2,653)	0
Net cash provided by financing activities	191,117	204,968
(Decrease) increase in cash	(192,706)	3,834
Cash at beginning of period	212,884	16,732
Cash at end of period	$ 20,178	$ 20,566