Employee Benefit Plans - Summary of Changes in Benefit Obligations, Fair Value of Assets, Funded Status and Amounts Recognized in Consolidated Statements of Financial Condition (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Tax benefits on amounts recognized in OCI	$ 41,253	$ 41,298