Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents		$ 514	$ 38,560
Accrued production receivable		127,216	125,788
Trade and other receivables, net		27,949	26,970
Derivative assets		55,615	93,080
Other current assets		11,491	11,896
Total current assets		222,785	296,294
Oil and natural gas properties (using full cost accounting)
Proved properties		11,315,866	11,072,209
Unevaluated properties		942,859	996,700
CO2 properties		1,199,339	1,196,795
Pipelines and plants		2,327,671	2,302,817
Other property and equipment		215,794	250,279
Less accumulated depletion, depreciation, amortization and impairment		(11,629,245)	(11,500,190)
Net property and equipment		4,372,284	4,318,610
Operating lease right-of-use assets		35,145	0
Derivative assets		11,483	4,195
Other assets		112,013	104,123
Total assets		4,753,710	4,723,222
Current liabilities
Accounts payable and accrued liabilities		159,256	198,380
Oil and gas production payable		58,881	61,288
Current maturities of long-term debt (including future interest payable of $85,909 and $85,303, respectively - see Note 4)	[1]	100,626	105,125
Operating lease liabilities		6,710	0
Total current liabilities		325,473	364,793
Long-term liabilities
Long-term debt, net of current portion (including future interest payable of $104,501 and $164,914, respectively - see Note 4)		2,409,683	2,664,211
Asset retirement obligations		175,716	174,470
Deferred tax liabilities, net		400,213	309,758
Operating lease liabilities		43,704	0
Other liabilities		52,801	68,213
Total long-term liabilities		3,082,117	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, 750,000,000 shares authorized; 473,213,227 and 462,355,725 shares issued, respectively		473	462
Paid-in capital in excess of par		2,698,158	2,685,211
Accumulated deficit		(1,339,232)	(1,533,112)
Treasury stock, at cost, 3,620,785 and 1,941,749 shares, respectively		(13,279)	(10,784)
Total stockholders' equity		1,346,120	1,141,777
Total liabilities and stockholders' equity		$ 4,753,710	$ 4,723,222

[1] Our current maturities of long-term debt as of September 30, 2019 include $85.9 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.