Debt - Additional Information (Detail) (USD $)				9 Months Ended		0 Months Ended	1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2014 Minimum [Member]	Sep. 30, 2014 Maximum [Member]	Jun. 26, 2013 12% Senior Unsecured PIK Notes Due 2018 [Member]	Dec. 31, 2013 12% Senior Unsecured PIK Notes Due 2018 [Member]	Sep. 30, 2014 12% Senior Unsecured PIK Notes Due 2018 [Member]	Sep. 30, 2014 12% Senior Unsecured PIK Notes Due 2018 [Member]	Jan. 15, 2014 12% Senior Unsecured PIK Notes Due 2018 [Member]	Jun. 26, 2013 12% Senior Unsecured PIK Notes Due 2018 [Member]	Sep. 30, 2014 12% Senior Unsecured PIK Notes Due 2018 [Member] Interest Paid in Cash [Member]	Sep. 30, 2014 12% Senior Unsecured PIK Notes Due 2018 [Member] Paid In Kind Interest [Member]	Jan. 15, 2014 12% Senior Unsecured PIK Notes Due 2018 [Member] Paid In Kind Interest [Member]	Sep. 30, 2014 12% Senior Unsecured PIK Notes Due 2018 [Member] Level 2 [Member]
Debt Instrument [Line Items]
Aggregate principal amount							$ 100,000,000				$ 300,000,000
Debt instrument interest rate											12.00%	12.00%	13.00%
Notes issued percentage of par											96.00%
Proceeds from debt instrument						280,700,000	100,000,000
Debt discount	9,000,000		10,800,000				0				12,000,000
Offering expenses						7,300,000	200,000
Amortization of deferred financing costs and debt discount								1,000,000	3,000,000
Senior unsecured notes redemption price description									The Company has the right to redeem all or a portion of the Senior Unsecured Notes prior to the 2-year anniversary of the final funding date, which the Company refers to as the Non-Call Period, by paying a redemption price equal to 100.0% times a “make whole premium” equal to the greater of 106.0% or an amount computed under the Indenture governing the Senior Unsecured Notes (the “Indenture”) plus accrued and unpaid interest.
Percentage of interest payments per annum												6.00%	7.00%
Accrued interest								10,600,000	10,600,000	25,300,000				22,500,000
Capitalized interest expense								3,700,000	6,300,000
Interest payments terms									Interest is payable on July 15 and January 15 each year, beginning in January 2014
Principal amount outstanding								422,500,000	422,500,000
Fair value															484,000,000
Revolving credit facility		500,000,000
Borrowing base	100,000,000
Outstanding letters of credit	25,000,000
Outstanding borrowings	0
Available capacity on the Revolving Credit Facility	$ 75,000,000
Commitment fees on unused portion of revolving credit facility				0.375%	0.50%