Related-Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Advertising Related and Other Services
Related Party Transaction [Line Items]
Purchase of marketing services	$ 18.1	$ 92.4
Marketing Services
Related Party Transaction [Line Items]
Purchase of marketing services	$ 1.9	$ 4.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration