Equity Based Compensation - Summary of Option Activity for Stock Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Outstanding, Beginning balance	747,500
Shares, Granted
Shares, Exercised
Shares, Expired	(90,000)
Shares, Forfeited
Shares, Outstanding, Ending balance	657,500		747,500
Shares, Exercisable	606,662
Shares, Expected to vest	49,589
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 12.32
Weighted Average Exercise Price, Granted
Weighted Average Exercise Price, Exercised
Weighted Average Exercise Price, Expired	$ 27.15
Weighted Average Exercise Price, Forfeited
Weighted Average Exercise Price, Outstanding, Ending balance	$ 10.29		$ 12.32
Weighted Average Exercise Price, Exercisable	$ 10.55
Weighted Average Exercise Price, Expected to vest	$ 7.23
Weighted Average Remaining Contractual Life (Yrs.), Outstanding	5 years 11 months 12 days		5 years 11 months 1 day
Weighted Average Remaining Contractual Life (Yrs.), Exercisable	5 years 9 months 29 days
Weighted Average Remaining Contractual Life (Yrs.), Expected to vest	7 years 5 months 23 days
Aggregate Intrinsic Value, Outstanding	$ 8,302
Aggregate Intrinsic Value, Exercisable	7,547
Aggregate Intrinsic Value, Expected to vest	$ 737