Borrowed Funds - Scheduled Securities Sold Under Repurchase Agreements (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total securities sold under repurchase agreements	$ 114,004	$ 99,936
Securities Loaned or Sold under Agreements to Repurchase
Debt Instrument [Line Items]
Due in one year or less	114,004
Due after one year through two years	0
Due after two years through three years	0
Due after three years through four years	0
Due after four years through five years	0
Thereafter	0
Total securities sold under repurchase agreements	$ 114,004