Subsequent Event - Additional Information (Detail) - USD ($)		9 Months Ended
	Oct. 05, 2015	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Subsequent Event [Line Items]
Interest paid		$ 16,095,000	$ 16,487,000
Interest payable		3,167,000		$ 6,917,000
Senior Notes [Member] | 7.75% Senior Secured Notes Due October 2020 [Member]
Subsequent Event [Line Items]
Direct debt issuance costs accrued		$ 8,500,000
Senior Notes [Member] | 12% Senior Secured Notes Due July 2017 [Member]
Subsequent Event [Line Items]
Senior secured notes, interest rate		12.00%
Senior secured notes, maturity date		Jul. 15, 2017
Senior Secured Notes, maturity year and month		2017-07
Interest payable		$ 3,167,000
Subsequent Event [Member] | Senior Notes [Member] | 7.75% Senior Secured Notes Due October 2020 [Member]
Subsequent Event [Line Items]
Senior secured notes, issued	$ 250,000,000
Senior secured notes, interest rate	7.75%
Senior secured notes, maturity date	Oct. 05, 2020
Frequency of payment	Quarterly
Date of first repayment	Oct. 15, 2015
Issuance costs	$ 8,800,000
Subsequent Event [Member] | Senior Notes [Member] | 12% Senior Secured Notes Due July 2017 [Member]
Subsequent Event [Line Items]
Senior secured notes, interest rate	12.00%
Repayment of senior secured notes	$ 125,000,000
Redemption premium	11,300,000
Interest paid	4,500,000
Subsequent Event [Member] | Senior Secured Notes [Member] | 7.75% Senior Secured Notes Due October 2020 [Member]
Subsequent Event [Line Items]
Senior secured notes, cash received	$ 100,400,000