Equity Based Compensation - Summary of Option Activity for Stock Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Outstanding, Beginning balance	747,500
Shares, Granted	0	0
Shares, Exercised
Shares, Expired	(90,000)
Shares, Forfeited
Shares, Outstanding, Ending balance	657,500		747,500
Shares, Exercisable	601,662
Shares, Expected to vest	53,929
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	$ 10.58
Weighted Average Exercise Price, Expected to vest	$ 7.14
Weighted Average Remaining Contractual Life (Yrs.), Outstanding	6 years 2 months 16 days		5 years 11 months 1 day
Weighted Average remaining Contractual Life (Yrs.), Exercisable	6 years 22 days
Weighted Average remaining Contractual Life (Yrs.), Expected to vest	7 years 9 months 7 days
Aggregate Intrinsic Value, Outstanding	$ 0
Aggregate Intrinsic Value, Granted	0
Aggregate Intrinsic Value, Exercised	0
Aggregate Intrinsic Value, Expired	0
Aggregate Intrinsic Value, Forfeited	0
Aggregate Intrinsic Value, Outstanding	6,623		0
Aggregate Intrinsic Value, Exercisable	5,941
Aggregate Intrinsic Value, Expected to vest	$ 659