Loans - Loans (Parenthetical) (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans receivable	$ 4,825,642	$ 4,610,147
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans receivable	12,126	13,670
Consumer | Home equity line of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans receivable	$ 7,600	$ 8,200