Loans - Loans (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans receivable	$ 4,543,636	$ 4,610,147
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans receivable	12,090	13,670
Consumer | Home equity line of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans receivable	$ 7,500	$ 8,200