Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 1,086,160	$ 1,033,782
Less: accumulated depreciation	(387,798)	(336,067)
Total property and equipment, net	698,362	697,715
Capital leased assets, gross	101,300	106,800
Capital leases accumulated depreciation	37,900	30,400
Depreciation and amortization expense	60,800	60,000	$ 62,300
Buildings
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	548,232	531,627
Furniture and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	236,634	218,623
Software
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	134,321	124,469
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	108,702	106,768
Computers
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	58,271	52,295
Internal Use Software
Property, Plant and Equipment [Line Items]
Less: accumulated depreciation	(9,200)	(4,100)
Total property and equipment, net	$ 17,800	$ 15,400