Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Goodwill and Other Intangible Assets [Line Items]
Goodwill	$ 437,977,000		$ 437,977,000
Accumulated impairment losses on goodwill	279,000,000.0
Impairment charge for goodwill	0	$ 262,000,000
Amortization expense	3,166,000	4,432,000
Definite-lived Trademarks and Tradenames, Publishing Rights and Customer Related and Other Intangibles [Member]
Goodwill and Other Intangible Assets [Line Items]
Amortization expense	$ 11,100,000	$ 10,300,000