Quarterly report pursuant to Section 13 or 15(d)

Supplemental Guarantor Information (Condensed Consolidating Balance Sheet) (Details)

v2.4.0.6
Supplemental Guarantor Information (Condensed Consolidating Balance Sheet) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2012
Dec. 31, 2011
Mar. 31, 2011
Dec. 31, 2010
Cash and cash equivalents $ 8,508 $ 4,512 $ 58,393 $ 28,655
Oil and natural gas sales 89,034 98,550    
Joint interest and other 27,611 25,804    
Total receivables 116,645 124,354    
Deferred income taxes 11,004 2,007    
Prepaid expenses and other assets 22,139 30,315    
Total current assets 158,296 161,188    
Oil and natural gas properties and equipment 6,018,210 5,959,016    
Furniture, fixtures and other 20,001 19,500    
Total property and equipment 6,038,211 5,978,516    
Less accumulated depreciation, depletion and amortization 4,403,418 4,320,410    
Net property and equipment 1,634,793 1,658,106    
Restricted deposits for asset retirement obligations 35,518 33,462    
Other assets 13,734 16,169    
Total assets 1,842,341 1,868,925    
Accounts payable 64,992 75,871    
Undistributed oil and natural gas proceeds 35,075 33,732    
Asset retirement obligations 105,442 138,185    
Accrued liabilities 55,049 29,705    
Income taxes 313 10,392    
Total current liabilities 260,871 287,885    
Long-term debt 684,000 717,000    
Asset retirement obligations, less current portion 263,037 255,695    
Deferred income taxes 70,427 58,881    
Other liabilities 19,590 4,890    
Commitments and contingencies          
Common stock 1 1    
Additional paid-in capital 389,628 386,920    
Retained earnings 178,954 181,820    
Treasury stock, at cost (24,167) (24,167)    
Total shareholders' equity 544,416 544,574    
Total liabilities and shareholders' equity 1,842,341 1,868,925    
Parent Company [Member]
        
Cash and cash equivalents 8,508 4,512 58,393 28,655
Oil and natural gas sales 69,944 78,131    
Joint interest and other 27,611 25,804    
Income taxes 94,642 74,183    
Total receivables 192,197 178,118    
Deferred income taxes 11,004 2,007    
Prepaid expenses and other assets 22,139 30,315    
Total current assets 233,848 214,952    
Oil and natural gas properties and equipment 5,737,812 5,689,535    
Furniture, fixtures and other 20,001 19,500    
Total property and equipment 5,757,813 5,709,035    
Less accumulated depreciation, depletion and amortization 4,271,613 4,208,825    
Net property and equipment 1,486,200 1,500,210    
Restricted deposits for asset retirement obligations 35,518 33,462    
Other assets 388,653 372,572    
Total assets 2,144,219 2,121,196    
Accounts payable 64,261 73,333    
Undistributed oil and natural gas proceeds 34,836 33,391    
Asset retirement obligations 105,442 138,185    
Accrued liabilities 55,049 29,705    
Total current liabilities 259,588 274,614    
Long-term debt 684,000 717,000    
Asset retirement obligations, less current portion 235,113 228,419    
Deferred income taxes 88,477 76,518    
Other liabilities 332,624 280,071    
Common stock 1 1    
Additional paid-in capital 389,629 386,920    
Retained earnings 178,954 181,820    
Treasury stock, at cost (24,167) (24,167)    
Total shareholders' equity 544,417 544,574    
Total liabilities and shareholders' equity 2,144,219 2,121,196    
Guarantor Subsidiaries [Member]
        
Oil and natural gas sales 19,090 20,419    
Total receivables 19,090 20,419    
Total current assets 19,090 20,419    
Oil and natural gas properties and equipment 280,398 269,481    
Total property and equipment 280,398 269,481    
Less accumulated depreciation, depletion and amortization 131,805 111,585    
Net property and equipment 148,593 157,896    
Deferred income taxes 18,050 17,637    
Other assets 313,034 275,181    
Total assets 498,767 471,133    
Accounts payable 731 2,538    
Undistributed oil and natural gas proceeds 239 341    
Income taxes 94,955 84,575    
Total current liabilities 95,925 87,454    
Asset retirement obligations, less current portion 27,924 27,276    
Additional paid-in capital 231,759 231,759    
Retained earnings 143,159 124,644    
Total shareholders' equity 374,918 356,403    
Total liabilities and shareholders' equity 498,767 471,133    
Eliminations [Member]
        
Income taxes (94,642) (74,183)    
Total receivables (94,642) (74,183)    
Total current assets (94,642) (74,183)    
Deferred income taxes (18,050) (17,637)    
Other assets (687,953) (631,584)    
Total assets (800,645) (723,404)    
Income taxes (94,642) (74,183)    
Total current liabilities (94,642) (74,183)    
Deferred income taxes (18,050) (17,637)    
Other liabilities (313,034) (275,181)    
Additional paid-in capital (231,760) (231,759)    
Retained earnings (143,159) (124,644)    
Total shareholders' equity (374,919) (356,403)    
Total liabilities and shareholders' equity $ (800,645) $ (723,404)