Goodwill and Other Intangibles - Narrative (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Finite-lived intangible assets	$ 518,190,000	$ 553,114,000
Intangible assets, accumulated amortization	286,900,000	248,000,000.0
Impairment of amortizable intangible assets	$ 0	$ 0	$ 4,300,000