Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES:
Net income (loss)	$ (135,624)	$ (1,037,361)	$ 136,276
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation, depletion, and amortization	208,353	352,742	402,888
Impairments (Note 2)	161,563	1,634,628	158,069
Amortization of debt issuance costs and debt discount	2,122	2,088	2,055
(Gain) loss on derivatives	22,813	(26,345)	(30,147)
Cash (payments) receipts on derivatives settled	9,658	46,615	(6,038)
(Gain) loss on disposition of assets	(3,127)	7,229	(8,953)
Deferred tax expense (benefit)	(71,209)	(606,332)	77,285
Employee stock compensation plans	13,812	21,468	24,320
Bad debt expense	785	1,191	3,562
ARO liability accretion	2,779	3,453	4,599
Other, net	(6,037)	(1,517)	1,068
Changes in operating assets and liabilities increasing (decreasing) cash:
Accounts receivable	(11,796)	105,426	(60,800)
Materials and supplies	225	1,507	2,602
Prepaid expenses and other	2,585	7,134	6,550
Accounts payable	27,400	(20,306)	4,715
Accrued liabilities	(4,388)	(22,920)	(1,297)
Income taxes	20,903	(21,482)	(6,994)
Contract advances	(687)	(274)	(767)
Net cash provided by operating activities	240,130	446,944	708,993
INVESTING ACTIVITIES:
Capital expeditures	(186,149)	(561,453)	(981,374)
Producing property and other acquisitions	(564)	(179)	(5,723)
Proceeds from disposition of property and equipment	74,823	11,854	66,197
Other	919	0	303
Net cash used in investing activities	(110,971)	(549,778)	(920,597)
FINANCING ACTIVITIES:
Borrowings under line of credit	251,398	618,500	725,800
Payments under line of credit	(371,600)	(503,500)	(559,800)
Payments on capitalized leases	(3,694)	(3,549)	(2,392)
Proceeds from exercise of stock options	0	0	1,083
Tax (expense) benefit from stock compensation	(376)	(3,207)	1,614
Increase (decrease) in book overdrafts (Note 2)	(4,829)	(5,624)	27,755
Net cash provided by (used in) financing activities	(129,101)	102,620	194,060
Net increase (decrease) in cash and cash equivalents	58	(214)	(17,544)
Cash and cash equivalents, beginning of year	835	1,049	18,593
Cash and cash equivalents, end of year	893	835	1,049
Supplemental disclosure of cash flow information:
Interest paid (net of capitalization)	35,690	30,910	13,620
Income taxes	42	3,540	15,898
Changes in accounts payable and accrued liabilities related to purchases of property, plant, and equipment	21,190	105,157	(31,968)
Non-cash reductions to oil and natural gas properties related to asset retirement obligations	30,897	5,694	37,689
Non-cash additions to property, plant, and equipment acquired under capital leases	$ 0	$ 0	$ (28,202)