Goodwill and Other Intangible Assets Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 392,900			$ 392,900		$ 659,900
Total other intangible assets, net	694,400			694,400		$ 830,300
Amortization of intangible assets	8,700		$ 10,400	27,500	$ 30,900
Estimated Future Amortization Expense by Fiscal Year [Abstract]
Remainder of 2016	8,700			8,700
2017	33,300			33,300
2018	28,300			28,300
2019	25,700			25,700
2020	25,000			25,000
2021	25,000			25,000
After 2021	$ 214,700			$ 214,700
Deferred Income Taxes and Tax Credits		$ 90,300
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)		$ 108,900