CONDENSED CONSOLIDATED BALANCE SHEET (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 740,994	$ 480,047
Accounts receivable, net	180,545	216,004
Income taxes receivable	41,512	56,666
Inventories	20,470	8,006
Current assets held for sale	0	1,440
Other current assets	3,892	2,794
Total current assets	987,413	764,957
Properties and equipment, net (Successful efforts method)	3,225,493	3,072,204
Equity method investments	147,984	86,077
Assets held for sale	6,828	778,855
Derivative instruments	3,412	2,239
Other assets	25,580	23,012
TOTAL ASSETS	4,396,710	4,727,344
Current liabilities
Accounts payable	235,978	238,045
Current portion of long-term debt	304,000	304,000
Accrued liabilities	13,817	27,441
Interest payable	27,360	27,575
Derivative instruments	9,589	30,637
Current liabilities held for sale	0	2,352
Total current liabilities	590,744	630,050
Long-term debt, net	1,218,572	1,217,891
Deferred income taxes	293,927	227,030
Asset retirement obligations	46,527	43,601
Liabilities held for sale	1,867	15,748
Postretirement benefits	30,351	29,396
Other liabilities	60,548	39,723
Total liabilities	2,242,536	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	47,609	47,555
Additional paid-in capital	1,749,437	1,742,419
Retained earnings	1,266,928	1,162,430
Accumulated other comprehensive income (loss)	2,248	2,077
Less treasury stock, at cost: 12,935,926 and 9,892,680 shares in 2017 and 2016, respectively	(912,048)	(430,576)
Total stockholders' equity	2,154,174	2,523,905
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 4,396,710	$ 4,727,344

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).