Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES:
Net income (loss)	$ (1,037,361)	$ 136,276	$ 184,746
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation, depletion, and amortization	354,830	404,943	333,907
Impairment of properties (Note 2)	1,634,628	158,069	0
(Gain) loss on derivatives	(26,345)	(30,147)	7,771
Cash (payments) receipts on derivatives settled	46,615	(6,038)	(1,161)
(Gain) loss on disposition of assets	7,229	(8,953)	(17,076)
Deferred tax expense (benefit)	(606,332)	77,285	100,732
Employee stock compensation plans	21,468	24,320	21,317
Bad debt expense	1,191	3,562	0
ARO liability accretion	3,453	4,599	5,450
Other, net	(1,517)	1,068	2,250
Changes in operating assets and liabilities increasing (decreasing) cash:
Accounts receivable	105,426	(60,800)	2,967
Materials and supplies	1,507	2,602	(2,435)
Prepaid expenses and other	(14,348)	(444)	1,813
Accounts payable	(20,306)	4,715	15,715
Accrued liabilities	(22,920)	(1,297)	17,198
Contract advances	(274)	(767)	1,137
Net cash provided by operating activities	446,944	708,993	674,331
INVESTING ACTIVITIES:
Capital expeditures	(561,453)	(981,374)	(703,984)
Producing property and other acquisitions	(179)	(5,723)	0
Proceeds from disposition of property and equipment	11,854	66,197	120,910
Other	0	303	3,894
Net cash used in investing activities	(549,778)	(920,597)	(579,180)
FINANCING ACTIVITIES:
Borrowings under line of credit	618,500	725,800	222,500
Payments under line of credit	(503,500)	(559,800)	(293,600)
Payments on capitalized leases	(3,549)	(2,392)	0
Proceeds from exercise of stock options	0	1,083	574
Excess Tax Benefit from Share-based Compensation, Financing Activities	(3,207)	1,614	8
Increase (decrease) in book overdrafts (Note 2)	(5,624)	27,755	(7,014)
Net cash provided by (used in) financing activities	102,620	194,060	(77,532)
Net increase (decrease) in cash and cash equivalents	(214)	(17,544)	17,619
Cash and cash equivalents, beginning of year	1,049	18,593	974
Cash and cash equivalents, end of year	835	1,049	18,593
Supplemental disclosure of cash flow information:
Interest paid (net of capitalization)	30,910	13,620	12,485
Income taxes	3,540	15,898	9,100
Changes in accounts payable and accrued liabilities related to purchases of property, plant, and equipment	105,157	(31,968)	(6,550)
Non-cash reductions to oil and natural gas properties related to asset retirement obligations	5,694	37,689	17,952
Non-cash additions to property, plant, and equipment acquired under capital leases	$ 0	$ (28,202)	$ 0