Quarterly report pursuant to Section 13 or 15(d)

Condensed Consolidating Balance Sheet (Detail)

v2.4.0.6
Condensed Consolidating Balance Sheet (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2013
Dec. 31, 2012
Mar. 31, 2012
Dec. 31, 2011
Current assets:        
Cash and cash equivalents $ 12,277 $ 12,245 $ 8,508 $ 4,512
Receivables:        
Oil and natural gas sales 97,309 97,733    
Joint interest and other 35,681 56,439    
Income taxes 45,638 47,884    
Total receivables 178,628 202,056    
Deferred income taxes 1,432 267    
Prepaid expenses and other assets 22,363 25,555    
Total current assets 214,700 240,123    
Property and equipment - at cost:        
Oil and natural gas properties and equipment 6,836,590 6,694,510    
Furniture, fixtures and other 21,949 21,786    
Total property and equipment 6,858,539 6,716,296    
Less accumulated depreciation, depletion and amortization 4,759,198 4,655,841    
Net property and equipment 2,099,341 2,060,455    
Restricted deposits for asset retirement obligations 29,161 28,466    
Deferred income taxes          
Other assets 18,855 19,943    
Total assets 2,362,057 2,348,987    
Current liabilities:        
Accounts payable 112,223 123,885    
Undistributed oil and natural gas proceeds 41,255 37,073    
Asset retirement obligations 69,964 92,630    
Accrued liabilities 39,067 21,021    
Total current liabilities 262,509 274,609    
Long-term debt 1,060,079 1,087,611    
Asset retirement obligations, less current portion 308,261 291,423    
Deferred income taxes 158,922 145,249    
Other liabilities 8,288 8,908    
Shareholders' equity:        
Common stock 1 1    
Additional paid-in capital 398,465 396,186    
Retained earnings 189,699 169,167    
Treasury stock, at cost (24,167) (24,167)    
Total shareholders' equity 563,998 541,187    
Total liabilities and shareholders' equity 2,362,057 2,348,987    
Parent Company
        
Current assets:        
Cash and cash equivalents 12,277 12,245 8,508 4,512
Receivables:        
Oil and natural gas sales 80,556 80,729    
Joint interest and other 35,681 56,439    
Income taxes 167,708 163,750    
Total receivables 283,945 300,918    
Deferred income taxes 1,432 267    
Prepaid expenses and other assets 22,363 25,555    
Total current assets 320,017 338,985    
Property and equipment - at cost:        
Oil and natural gas properties and equipment 6,480,011 6,356,529    
Furniture, fixtures and other 21,949 21,786    
Total property and equipment 6,501,960 6,378,315    
Less accumulated depreciation, depletion and amortization 4,543,468 4,461,886    
Net property and equipment 1,958,492 1,916,429    
Restricted deposits for asset retirement obligations 29,161 28,466    
Deferred income taxes          
Other assets 454,552 442,540    
Total assets 2,762,222 2,726,420    
Current liabilities:        
Accounts payable 112,207 123,792    
Undistributed oil and natural gas proceeds 41,011 36,791    
Asset retirement obligations 69,964 92,595    
Accrued liabilities 38,676 20,755    
Total current liabilities 261,858 273,933    
Long-term debt 1,060,079 1,087,611    
Asset retirement obligations, less current portion 278,646 262,524    
Deferred income taxes 171,698 158,758    
Other liabilities 425,942 402,407    
Shareholders' equity:        
Common stock 1 1    
Additional paid-in capital 398,465 396,186    
Retained earnings 189,700 169,167    
Treasury stock, at cost (24,167) (24,167)    
Total shareholders' equity 563,999 541,187    
Total liabilities and shareholders' equity 2,762,222 2,726,420    
Guarantor Subsidiaries
        
Current assets:        
Cash and cash equivalents            
Receivables:        
Oil and natural gas sales 16,753 17,004    
Joint interest and other          
Income taxes          
Total receivables 16,753 17,004    
Deferred income taxes          
Prepaid expenses and other assets          
Total current assets 16,753 17,004    
Property and equipment - at cost:        
Oil and natural gas properties and equipment 356,579 337,981    
Furniture, fixtures and other          
Total property and equipment 356,579 337,981    
Less accumulated depreciation, depletion and amortization 215,730 193,955    
Net property and equipment 140,849 144,026    
Restricted deposits for asset retirement obligations          
Deferred income taxes 12,776 13,509    
Other assets 417,655 393,499    
Total assets 588,033 568,038    
Current liabilities:        
Accounts payable 16 93    
Undistributed oil and natural gas proceeds 244 282    
Asset retirement obligations          
Accrued liabilities 122,461 116,132    
Total current liabilities 122,721 116,507    
Long-term debt          
Asset retirement obligations, less current portion 29,615 28,934    
Deferred income taxes          
Other liabilities          
Shareholders' equity:        
Common stock          
Additional paid-in capital 231,759 231,759    
Retained earnings 203,938 190,838    
Treasury stock, at cost          
Total shareholders' equity 435,697 422,597    
Total liabilities and shareholders' equity 588,033 568,038    
Eliminations
        
Current assets:        
Cash and cash equivalents            
Receivables:        
Oil and natural gas sales          
Joint interest and other          
Income taxes (122,070) (115,866)    
Total receivables (122,070) (115,866)    
Deferred income taxes          
Prepaid expenses and other assets          
Total current assets (122,070) (115,866)    
Property and equipment - at cost:        
Oil and natural gas properties and equipment          
Furniture, fixtures and other          
Total property and equipment          
Less accumulated depreciation, depletion and amortization          
Net property and equipment          
Restricted deposits for asset retirement obligations          
Deferred income taxes (12,776) (13,509)    
Other assets (853,352) (816,096)    
Total assets (988,198) (945,471)    
Current liabilities:        
Accounts payable          
Undistributed oil and natural gas proceeds          
Asset retirement obligations    35    
Accrued liabilities (122,070) (115,866)    
Total current liabilities (122,070) (115,831)    
Long-term debt          
Asset retirement obligations, less current portion    (35)    
Deferred income taxes (12,776) (13,509)    
Other liabilities (417,654) (393,499)    
Shareholders' equity:        
Common stock          
Additional paid-in capital (231,759) (231,759)    
Retained earnings (203,939) (190,838)    
Treasury stock, at cost          
Total shareholders' equity (435,698) (422,597)    
Total liabilities and shareholders' equity $ (988,198) $ (945,471)