Description of Business and Summary of Significant Accounting Policies (Revenue Recognition, Advertising) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Advertising [Abstract]
Advertising expense, net	$ 187.8	$ 197.8	$ 192.8
Manufacturer advertising reimbursements	$ 59.8	$ 66.1	$ 65.0

Total amount received by an entity from a vendor under a cooperative advertising arrangement that has been offset against advertising expense.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 705
-SubTopic 20
-Section 25
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=68067574&loc=SL51760044-203187

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 720
-SubTopic 35
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848

Name:	us-gaap_CooperativeAdvertisingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration