CONDENSED CONSOLIDATED BALANCE SHEET (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 516,534	$ 498,542
Accounts receivable, net	177,342	191,045
Income taxes receivable	16,464	10,298
Inventories	11,080	13,304
Current assets held for sale	2,228	0
Other current assets	12,176	2,692
Total current assets	735,824	715,881
Properties and equipment, net (Successful efforts method)	4,202,985	4,250,125
Equity method investments	140,581	129,524
Assets held for sale	111,321	0
Other assets	28,748	27,039
TOTAL ASSETS	5,219,459	5,122,569
Current liabilities
Accounts payable	183,554	168,411
Accrued liabilities	20,841	21,492
Interest payable	27,339	27,650
Derivative instruments	2,688	40,259
Total current liabilities	234,422	257,812
Long-term debt, net	1,521,211	1,520,530
Deferred income taxes	617,332	579,447
Asset retirement obligations	57,502	131,733
Liabilities held for sale	75,693	0
Postretirement benefits	37,208	36,259
Other liabilities	34,060	29,121
Total liabilities	2,577,428	2,554,902
Commitments and contingencies
Stockholders' equity
Common stock: Authorized - 960,000,000 shares of $0.10 par value in 2017 and 2016 Issued - 475,428,710 shares and 475,042,692 shares in 2017 and 2016, respectively	47,543	47,504
Additional paid-in capital	1,733,312	1,727,310
Retained earnings	1,235,540	1,098,703
Accumulated other comprehensive income	726	985
Less treasury stock, at cost: 9,892,680 shares in 2016 and 2015, respectively	(375,090)	(306,835)
Total stockholders' equity	2,642,031	2,567,667
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 5,219,459	$ 5,122,569

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).