Property and Equipment, Net - Summary of Property and Equipment, Net (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipment	$ 407,365	$ 330,401
Less accumulated depreciation and amortization	(78,942)	(61,239)
Property and equipment, net	328,423	269,162
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	18,591	13,294
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	5,176	3,439
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	213,703	180,945
Equipment under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	5,310	5,310
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	29,306	24,930
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	62,527	55,734
Furniture, Fixtures and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	31,035	22,124
Internally Developed Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	14,422	11,039
Other [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	1,099	1,099
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 26,196	$ 12,487