Fair Value Measurements - Financial Assets and Liabilities, Excluding Cash and Cash Equivalents, Measured on a Recurring Basis at Fair Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Mutual fund assets	$ 32,542	$ 30,652
Derivative assets:
Foreign currency contracts	361	335
Total assets at fair value	32,903	30,987
Derivative liabilities:
Foreign currency contracts	385	566
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Mutual fund assets	32,542	30,652
Derivative assets:
Total assets at fair value	32,542	30,652
Level 2 [Member]
Derivative assets:
Foreign currency contracts	361	335
Total assets at fair value	361	335
Derivative liabilities:
Foreign currency contracts	$ 385	$ 566