Property and Equipment - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Total capital leased assets, gross	$ 94.8	$ 100.9
Capital leases accumulated depreciation	34.0	43.4
Depreciation expense	$ 72.4	$ 61.4	$ 60.8