Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 895	$ 18,593
Accounts receivable, net of allowance for doubtful accounts of $2,292 and $5,342 at September 30, 2014 and at December 31, 2013, respectively	179,464	139,788
Materials and supplies	8,776	10,998
Current derivative asset (Note 9)	4,047	515
Current deferred tax asset	13,585	13,585
Assets held for sale	0	15,621
Prepaid expenses and other	13,360	12,931
Total current assets	220,127	212,031
Oil and natural gas properties on the full cost method:
Proved properties	4,696,879	4,235,712
Unproved properties not being amortized	584,270	545,588
Drilling equipment	1,569,202	1,477,093
Gas gathering and processing equipment	606,815	549,422
Transportation equipment	40,402	39,666
Other	107,965	87,435
Property, Plant and Equipment, Gross	7,605,533	6,934,916
Less accumulated depreciation, depletion, amortization, and impairment	3,480,885	3,212,225
Net property and equipment	4,124,648	3,722,691
Debt issuance cost	10,653	11,844
Goodwill	62,808	62,808
Non-current derivative asset (Note 9)	658	0
Other assets	12,917	13,016
Total assets	4,431,811	4,022,390
Current liabilities:
Accounts payable	237,736	154,062
Accrued liabilities (Note 4)	83,930	64,363
Income taxes payable	15,452	7,474
Current derivative liabilities (Note 9)	0	5,561
Current portion of other long-term liabilities (Note 5)	14,221	12,113
Total current liabilities	351,339	243,573
Long-term debt (Note 5)	676,843	645,696
Other long-term liabilities (Note 5)	147,214	158,331
Deferred income taxes	888,915	801,398
Shareholders' equity:
Preferred stock, $1.00 par value, 5,000,000 shares authorized, none issued	0	0
Common stock, $.20 par value, 175,000,000 shares authorized, 49,574,708 and 49,107,004 shares issued, respectively	9,730	9,659
Capital in excess of par value	460,680	445,470
Retained earnings	1,897,090	1,718,263
Total shareholders' equity	2,367,500	2,173,392
Total liabilities and shareholders' equity	$ 4,431,811	$ 4,022,390