Fixed Assets, Net - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 7,500,000	$ 9,500,000	$ 24,500,000	$ 27,700,000
Fixed assets, net	13,474,000		13,474,000
Computer Software [Member]
Property, Plant and Equipment [Line Items]
Useful life of computer software	3 years		3 years
Software development costs capitalized	3,800,000	2,200,000	11,500,000	8,900,000
Aggregate amortization of software development costs	1,900,000	3,200,000	6,900,000	7,900,000
Impairment charges	$ 400,000	$ 100,000	$ 1,200,000	$ 1,100,000