Long-Term Debt - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended			9 Months Ended
	Apr. 12, 2011	Sep. 30, 2014	Apr. 15, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense		$ 1,700,000			$ 1,700,000
Senior Secured Notes [Member]
Debt Instrument [Line Items]
Private placement date	Apr. 12, 2011
Issuance of private placement, principal amount	200,000,000.0
Interest rate	8.75%	8.75%			8.75%
Term of payments of interest on notes	semi-annually
Cost to issue the notes	4,600,000
Total amount of debt to be retired			50,000,000
Percentage of debt to be retired from the total debt			25.00%
Aggregate face amount of debt redeemed			45,000,000
Redemption price as a percentage of face amount			106.563%
Outstanding principal amount of the debt			150,000,000
Annual interest cost reduction due to retirement of debt		3,900,000
Interest expense on note		3,300,000		4,300,000	11,000,000	12,800,000
Senior Secured Credit Note [Member]
Debt Instrument [Line Items]
Retirement of notes, principal amount	22,400,000
Subordinated Note [Member]
Debt Instrument [Line Items]
Retirement of notes, principal amount	100,000,000
November Two Thousand Eleven Senior Notes [Member]
Debt Instrument [Line Items]
Total amount of debt to be retired			$ 5,000,000