CONDENSED CONSOLIDATED BALANCE SHEET (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 964,928	$ 480,047
Accounts receivable, net	170,000	216,004
Income taxes receivable	81,420	56,666
Inventories	12,448	8,006
Derivative instruments	5,551	0
Current assets held for sale	0	1,440
Other current assets	1,771	2,794
Total current assets	1,236,118	764,957
Properties and equipment, net (Successful efforts method)	3,146,252	3,072,204
Equity method investments	120,501	86,077
Assets held for sale	6,807	778,855
Derivative instruments	5,762	2,239
Other assets	22,961	23,012
TOTAL ASSETS	4,538,401	4,727,344
Current liabilities
Accounts payable	174,662	238,045
Current portion of long-term debt	304,000	304,000
Accrued liabilities	11,570	27,441
Interest payable	12,257	27,575
Derivative instruments	8,002	30,637
Current liabilities held for sale	0	2,352
Total current liabilities	510,491	630,050
Long-term debt, net	1,218,231	1,217,891
Deferred income taxes	291,280	227,030
Asset retirement obligations	45,507	43,601
Liabilities held for sale	1,867	15,748
Postretirement benefits	29,722	29,396
Other liabilities	34,787	39,723
Total liabilities	2,131,885	2,203,439
Commitments and contingencies
Stockholders' equity
Common stock: Authorized - 960,000,000 shares of $0.10 par value in 2017 and 2016 Issued - 475,443,335 shares and 475,042,692 shares in 2017 and 2016, respectively	47,608	47,555
Additional paid-in capital	1,742,668	1,742,419
Retained earnings	1,251,568	1,162,430
Accumulated other comprehensive income (loss)	2,383	2,077
Less treasury stock, at cost: 12,935,926 and 9,892,680 shares in 2017 and 2016, respectively	(637,711)	(430,576)
Total stockholders' equity	2,406,516	2,523,905
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	4,538,401	4,727,344
Income taxes payable	$ 109	$ 0