Components of Selected Balance Sheet Accounts (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Other current assets:
Tubular inventory and well materials	$ 2,122	$ 2,271
Prepaid expenses	3,409	3,653
Other Assets, Miscellaneous, Current	100	0
Other Assets, Current	5,631	5,924
Other assets:
Debt issuance costs	28,339	30,239
Assets of supplemental employee retirement plan (“SERP”)	3,951	3,734
Other	563	562
Other assets	32,853	34,535
Accounts payable and accrued liabilities:
Trade accounts payable	112,835	120,278
Drilling and other lease operating costs	42,923	51,529
Royalties	45,089	39,929
Production and franchise taxes	5,198	5,338
Compensation - related	10,003	8,584
Interest	15,602	15,718
Preferred stock dividends	1,329	1,725
Liabilities of Assets Held-for-sale	1,224	0
Other	6,051	4,903
Accounts payable and accrued liabilities	240,254	248,004
Other liabilities:
Sale Leaseback Transaction Deferred Gain Noncurrent	9,989	0
Firm transportation obligation	12,533	13,245
Asset retirement obligations	5,669	6,437
Defined benefit pension obligations	1,491	1,579
Postretirement health care benefit obligations	1,112	1,023
Deferred compensation - SERP obligations and other	4,216	3,883
Other	9,891	7,219
Other liabilities	$ 44,901	$ 33,386