Income Taxes - Income Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
U.S. Federal									$ 38,732	$ 20,254	$ 18,334
U.S. State and local									8,203	5,457	3,218
Foreign									22,123	19,180	17,547
Total current income tax expense									69,058	44,891	39,099
Deferred:
U.S. Federal									(10,048)	9,180	8,123
U.S. State and local									(1,779)	1,210	1,142
Foreign									(1,419)	(2,972)	(139)
Total deferred income tax expense									(13,246)	7,418	9,126
Income tax expense	$ 18,527	$ 12,160	$ 16,486	$ 8,639	$ 12,627	$ 10,134	$ 17,438	$ 12,110	$ 55,812	$ 52,309	$ 48,225