Components of Selected Balance Sheet Accounts (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Description		0.1	24.6
Other current assets:
Tubular inventory and well materials		$ 2,878	$ 5,802
Prepaid expenses		4,184	4,215
Other		42	97
Prepaid Expense and Other Assets, Current, Total		7,104	10,114
Other assets: 1
Deferred issuance costs of the Revolver		1,572	1,623
Assets of supplemental employee retirement plan	[1]	4,123	4,123
Other		2,655	95
Other assets		8,350	5,841
Accounts payable and accrued liabilities:
Trade accounts payable		11,603	122,994
Drilling and other lease operating costs		12,074	68,842
Royalties		39,119	78,359
Compensation-related	[2]	9,904	9,197
Interest		15,531	15,555
Preferred stock dividends		0	6,067
Other		15,294	11,213
Accounts payable and accrued liabilities		103,525	312,227
Other liabilities:
Deferred gains on sales of assets		82,943	90,569
Firm transportation obligation		10,705	12,042
Asset retirement obligations		2,621	5,890
Defined benefit pension obligations		1,129	1,753
Postretirement health care benefit obligations		731	890
Compensation-related	[2]	1,447	7,630
Deferred compensation - supplemental employee retirement plan obligation and other	[1]	4,434	4,183
Other		928	929
Other liabilities		$ 104,938	$ 123,886

[1] .

[2] Includes liability-classified share-based compensation awards of $7.2 million and $2.9 million in Accounts payable and accrued expenses and an amount less than $0.1 million and $6.4 million in Other liabilities as of December 31, 2015 and 2014.