Commitments and Contingencies (Detail) $ in Millions	Dec. 31, 2019 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining aggregate obligation under the agreements with Nielsen Audio	$ 101.6

Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.

No definition available.

Name:	us-gaap_ContractualObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant