Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents		$ 5,749	$ 38,560
Accrued production receivable		147,379	125,788
Trade and other receivables, net		28,624	26,970
Derivative assets		14,012	93,080
Other current assets		10,282	11,896
Total current assets		206,046	296,294
Oil and natural gas properties (using full cost accounting)
Proved properties		11,140,781	11,072,209
Unevaluated properties		1,003,669	996,700
CO2 properties		1,196,868	1,196,795
Pipelines and plants		2,304,745	2,302,817
Other property and equipment		233,277	250,279
Less accumulated depletion, depreciation, amortization and impairment		(11,537,622)	(11,500,190)
Net property and equipment		4,341,718	4,318,610
Operating lease right-of-use assets		37,913	0
Derivative assets		2,022	4,195
Other assets		103,463	104,123
Total assets		4,691,162	4,723,222
Current liabilities
Accounts payable and accrued liabilities		147,324	198,380
Oil and gas production payable		65,893	61,288
Derivative liabilities		10,037	0
Current maturities of long-term debt (including future interest payable of $102,667 and $85,303, respectively - see Note 4)	[1]	120,258	105,125
Operating lease liabilities		7,070	0
Total current liabilities		350,582	364,793
Long-term liabilities
Long-term debt, net of current portion (including future interest payable of $147,550 and $164,914, respectively - see Note 4)		2,643,307	2,664,211
Asset retirement obligations		178,428	174,470
Derivative liabilities		306	0
Deferred tax liabilities, net		300,280	309,758
Operating lease liabilities		47,056	0
Other liabilities		51,883	68,213
Total long-term liabilities		3,221,260	3,216,652
Commitments and contingencies (Note 7)
Stockholders' equity
Preferred stock, $.001 par value, 25,000,000 shares authorized, none issued and outstanding		0	0
Common stock, $.001 par value, 600,000,000 shares authorized; 463,728,262 and 462,355,725 shares issued, respectively		464	462
Paid-in capital in excess of par		2,689,517	2,685,211
Accumulated deficit		(1,558,786)	(1,533,112)
Treasury stock, at cost, 2,473,243 and 1,941,749 shares, respectively		(11,875)	(10,784)
Total stockholders' equity		1,119,320	1,141,777
Total liabilities and stockholders' equity		$ 4,691,162	$ 4,723,222

[1] Future interest payable represents most of the interest due over the terms of our 9% Senior Secured Second Lien Notes due 2021 (the “2021 Senior Secured Notes”) and 9¼% Senior Secured Second Lien Notes due 2022 (the “2022 Senior Secured Notes”) and has been accounted for as debt in accordance with FASC 470-60, Troubled Debt Restructuring by Debtors. Our current maturities of long-term debt as of March 31, 2019 include $102.7 million of future interest payable related to the 2021 Senior Secured Notes and 2022 Senior Secured Notes that is due within the next twelve months.