Restrictions on Cash and Due from Banks and Interest-earning Deposit Accounts - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
Reserve requirement at Federal Reserve Bank	$ 11,100	$ 8,300
Average balances at Federal Reserve Bank	138,400	48,300
Pledging requirement for credit derivatives and SWAP agreements - cash	$ 0	$ 0