Components of Selected Balance Sheet Accounts (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Other current assets:
Tubular inventory and well materials	$ 3,946	$ 2,271
Prepaid expenses	2,905	3,653
Other Assets, Miscellaneous, Current	100	0
Other Assets, Current	6,951	5,924
Other assets:
Debt issuance costs	27,277	30,239
Assets of supplemental employee retirement plan (“SERP”)	4,021	3,734
Other	562	562
Other assets	31,860	34,535
Accounts payable and accrued liabilities:
Trade accounts payable	105,888	120,278
Drilling and other lease operating costs	56,585	51,529
Royalties	46,672	39,929
Compensation – related	10,947	8,584
Interest	37,417	15,718
Preferred stock dividends	7,638	1,725
Other	11,446	10,241
Accounts payable and accrued liabilities	276,593	248,004
Other liabilities:
Sale Leaseback Transaction Deferred Gain Noncurrent	90,675	0
Firm transportation obligation	12,352	13,245
Asset retirement obligations (“AROs”)	5,808	6,437
Defined benefit pension obligations	1,461	1,579
Postretirement health care benefit obligations	1,154	1,023
Deferred compensation – SERP obligations and other	4,130	3,883
Other	10,066	7,219
Other liabilities	$ 125,646	$ 33,386