Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,039,123	$ 991,782
Less accumulated depreciation	(585,247)	(542,583)
Property and equipment, net	453,876	449,199
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,476	7,476
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	6,487	6,293
Furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	64,843	61,582
Capitalized software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	917,825	866,398
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	41,031	29,420
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,461	$ 20,613