Condensed Consolidated Statements of Cash Flows - Unaudited - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities
Net income (loss)	$ 45,900	$ (107,667)
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Unrealized (gain) loss on derivatives	(20,631)	6,839
Depletion, depreciation and amortization	33,992	28,923
Accretion of asset retirement obligations	300	264
Full-cost ceiling impairment	0	80,462
Stock-based compensation expense	4,166	2,243
Amortization of debt issuance cost	44	300
Net gain on asset sales and inventory impairment	(7)	(1,065)
Changes in operating assets and liabilities
Accounts receivable	(16,777)	7,307
Lease and well equipment inventory	147	150
Prepaid expenses	(2,251)	(47)
Other assets	39	97
Accounts payable, accrued liabilities and other current liabilities	8,256	2,591
Royalties payable	6,984	(3,975)
Advances from joint interest owners	1,255	2,524
Income taxes payable	0	(2,463)
Other long-term liabilities	(108)	1,875
Net cash provided by operating activities	61,309	18,358
Investing activities
Oil and natural gas properties capital expenditures	(204,457)	(74,370)
Expenditures for other property and equipment	(20,867)	(27,409)
Proceeds from Sale of Oil and Gas Property and Equipment	350	0
Restricted cash	0	43,337
Restricted cash in less-than-wholly-owned subsidiaries	(13,346)	510
Net cash used in investing activities	(238,320)	(57,932)
Financing activities
Proceeds from issuance of common stock	0	142,350
Cost to issue equity	0	(614)
Proceeds from stock options exercised	1,981	0
Contributions related to formation of Joint Venture	171,500	0
Contributions from non-controlling interest owners of less-than-wholly-owned subsidiaries	4,900	0
Taxes paid related to net share settlement of stock-based compensation	(1,896)	(565)
Purchase of non-controlling interest of less-than-wholly-owned subsidiary	(2,653)	0
Net cash provided by financing activities	173,832	141,171
Increase in cash	(3,179)	101,597
Cash at beginning of period	212,884	16,732
Cash at end of period	$ 209,705	$ 118,329