Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	$ 3,640,226	$ 3,494,212
Accumulated depreciation	(1,513,462)	(1,428,555)
Property and equipment, net	2,126,764	2,065,657
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	268,521	267,051
Building [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	2,556,311	2,440,471
Furniture and Fixtures and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	715,507	647,988
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, gross	$ 99,887	$ 138,702