Summary of Significant Accounting Policies - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	$ 1,052,584	$ 895,219
Less - accumulated depreciation and amortization	(439,360)	(387,466)
Total property and equipment, net	613,224	507,753
Land
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	72,526	72,651
Buildings and improvements
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	173,214	156,417
Leasehold improvements
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	247,470	213,272
Furniture and equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	380,771	325,244
Software
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	51,792	46,366
Buildings held under capital leases
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	72,004	58,984
Equipment held under capital leases
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	62	55
Less - accumulated depreciation and amortization	(20,900)	(19,100)
Construction in progress
Property, Plant and Equipment, Net, by Type [Abstract]
Total property and equipment	$ 54,745	$ 22,230