CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ (186,131)	$ (414,941)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Impairments and other valuation losses	230,132	603,599
Depreciation, depletion and amortization	128,099	216,778
Asset retirement obligation	2,298	1,736
Deferred income taxes	(106,200)	(228,739)
Stock compensation	5,528	5,155
(Gain) loss on derivative instruments	(428)
Settlements on derivative instruments	5,068
Changes in non-current assets and liabilities	1,863	1,046
Other, net	1,362	2,311
Changes in operating assets and liabilities:
Receivables, net	33,147	72,397
Other current assets	11,982	9,894
Accounts payable and other current liabilities	(41,660)	(156,063)
Net cash provided by operating activities	85,060	113,173
Cash flows from investing activities:
Oil and gas expenditures	(176,395)	(371,106)
Sales of oil and gas assets and other assets	13,059	1,180
Other capital expenditures	(9,477)	(18,848)
Net cash used by investing activities	(172,813)	(388,774)
Cash flows from financing activities:
Dividends paid	(15,104)	(13,947)
Proceeds from exercise of stock options and other	114	4,618
Net cash provided by financing activities	(14,990)	(9,329)
Net change in cash and cash equivalents	(102,743)	(284,930)
Cash and cash equivalents at beginning of period	779,382	405,862
Cash and cash equivalents at end of period	$ 676,639	$ 120,932