Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Useful life	2 years 8 months 12 days
Amortization expense	$ 2,223,000	$ 3,351,000	$ 3,976,000
Write off of intangible assets	$ 0	$ 6,200,000	$ 7,600,000
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	2 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life	10 years