Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Lease commitment with media research and rating providers, aggregate amount	$ 10,500,000
Non-cancelable operating lease expiration term	2024-12
Lease commitments with research and rating providers annual commitments in 2021	$ 7,500,000
Lease commitments with research and rating providers annual commitments in 2022	1,400,000
Lease commitments with research and rating providers annual commitments after 2022	$ 1,600,000