Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 1,078	$ 18,593
Accounts receivable, net of allowance for doubtful accounts of $2,120 and $5,342 at June 30, 2014 and at December 31, 2013, respectively	177,149	139,788
Materials and supplies	8,540	10,998
Current derivative asset (Note 9)	0	515
Current deferred tax asset	13,585	13,585
Assets held for sale	0	15,621
Prepaid expenses and other	10,914	12,931
Total current assets	211,266	212,031
Oil and natural gas properties on the full cost method:
Proved properties	4,544,173	4,235,712
Unproved properties not being amortized	555,434	545,588
Drilling equipment	1,526,923	1,477,093
Gas gathering and processing equipment	592,191	549,422
Transportation equipment	40,301	39,666
Other	101,452	87,435
Property, plant, and equipment, gross, total	7,360,474	6,934,916
Less accumulated depreciation, depletion, amortization, and impairment	3,380,809	3,212,225
Net property and equipment	3,979,665	3,722,691
Debt issuance cost	11,050	11,844
Goodwill	62,808	62,808
Other assets	12,893	13,016
Total assets	4,277,682	4,022,390
Current liabilities:
Accounts payable	207,613	154,062
Accrued liabilities (Note 4)	65,744	64,363
Income taxes payable	10,776	7,474
Current derivative liabilities (Note 9)	15,839	5,561
Current portion of other long-term liabilities (Note 5)	14,578	12,113
Total current liabilities	314,550	243,573
Long-term debt (Note 5)	645,925	645,696
Non-current derivative liabilities (Note 9)	326	0
Other long-term liabilities (Note 5)	168,796	158,331
Deferred income taxes	853,398	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, 49,584,080 and 49,107,004 shares issued, respectively	9,729	9,659
Capital in excess of par value	455,390	445,470
Retained earnings	1,829,568	1,718,263
Total shareholders' equity	2,294,687	2,173,392
Total liabilities and shareholders' equity	$ 4,277,682	$ 4,022,390