CONSOLIDATED BALANCE SHEET - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 2,287	$ 480,047
Accounts receivable, net	362,403	216,004
Income taxes receivable	109,251	56,666
Inventories	11,076	8,006
Derivative instruments	57,665	0
Current assets held for sale	0	1,440
Other current assets	1,863	2,794
Total current assets	544,545	764,957
Properties and equipment, net (Successful efforts method)	3,463,606	3,072,204
Equity method investments	163,181	86,077
Assets held for sale	0	778,855
Derivative instruments	0	2,239
Other assets	27,497	23,012
TOTAL ASSETS	4,198,829	4,727,344
Current liabilities
Accounts payable	241,939	238,045
Current portion of long-term debt	0	304,000
Accrued liabilities	25,227	27,441
Interest payable	20,098	27,575
Derivative instruments	0	30,637
Current liabilities held for sale	0	2,352
Total current liabilities	287,264	630,050
Long-term debt, net	1,226,104	1,217,891
Deferred income taxes	458,597	227,030
Asset retirement obligations	50,622	43,601
Liabilities held for sale	0	15,748
Postretirement benefits	27,912	29,396
Other liabilities	60,171	39,723
Total liabilities	2,110,670	2,203,439
Commitments and contingencies
Stockholders' equity
Common stock	47,610	47,555
Additional paid-in capital	1,763,142	1,742,419
Retained earnings	1,607,658	1,162,430
Accumulated other comprehensive income	4,437	2,077
Treasury stock	(1,334,688)	(430,576)
Total stockholders' equity	2,088,159	2,523,905
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 4,198,829	$ 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).

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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).