Segments (Reconciliation of Assets from Segment to Consolidated) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total Assets	$ 5,692.0	$ 5,640.4	$ 5,384.0
Operating segments | Domestic
Segment Reporting Information [Line Items]
Total Assets	1,506.3		1,488.0
Operating segments | Import
Segment Reporting Information [Line Items]
Total Assets	1,317.1		1,224.2
Operating segments | Luxury
Segment Reporting Information [Line Items]
Total Assets	898.0		934.6
Corporate and other
Segment Reporting Information [Line Items]
Total Assets	$ 1,970.6		$ 1,737.2