Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents		$ 6,917	$ 516
Accrued production receivable		72,470	139,407
Trade and other receivables, net		41,497	18,318
Derivative assets		125,724	11,936
Other current assets		10,312	10,434
Total current assets		256,920	180,611
Oil and natural gas properties (using full cost accounting)
Proved properties		11,683,339	11,447,680
Unevaluated properties		636,656	872,910
CO2 properties		1,198,902	1,198,846
Pipelines and plants		2,335,198	2,329,078
Other property and equipment		217,066	212,334
Less accumulated depletion, depreciation, amortization and impairment		(11,854,989)	(11,688,020)
Net property and equipment		4,216,172	4,372,828
Operating lease right-of-use assets		32,886	34,099
Other assets		101,113	104,329
Total assets		4,607,091	4,691,867
Current liabilities
Accounts payable and accrued liabilities		106,546	183,832
Oil and gas production payable		46,921	62,869
Derivative liabilities		0	8,346
Current maturities of long-term debt (including future interest payable of $83,751 and $86,054, respectively - see Note 4)	[1]	98,212	102,294
Operating lease liabilities		7,044	6,901
Total current liabilities		258,723	364,242
Long-term liabilities
Long-term debt, net of current portion (including future interest payable of $59,998 and $78,860, respectively - see Note 4)		2,185,984	2,232,570
Asset retirement obligations		173,214	177,108
Deferred tax liabilities, net		406,021	410,230
Operating lease liabilities		40,112	41,932
Other liabilities		53,592	53,526
Total long-term liabilities		2,858,923	2,915,366
Commitments and contingencies (Note 8)
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; 508,415,378 and 508,065,495 shares issued, respectively		508	508
Paid-in capital in excess of par		2,742,303	2,739,099
Accumulated deficit		(1,247,298)	(1,321,314)
Treasury stock, at cost, 1,828,444 and 1,652,771 shares, respectively		(6,068)	(6,034)
Total stockholders' equity		1,489,445	1,412,259
Total liabilities and stockholders' equity		$ 4,607,091	$ 4,691,867

[1] Our current maturities of long-term debt as of March 31, 2020 include $83.8 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.