Summary of Fixed-To-Floating Rate Subordinated Notes Outstanding (Parenthetical) (Detail) - Subordinated Debt	12 Months Ended
	Dec. 31, 2019
Interest rate	5.90%	[1]
Description of variable rate basis	LIBOR rate plus 278 basis point
Debt instrument spread on variable rate	278.00%

[1] From and including the date of original issuance to, but excluding November 6, 2023, the Notes will bear interest at an initial rate of 5.90% per annum payable semi-annually. Unless redeemed, from and including November 6, 2023 to but excluding the maturity date, the interest rate will reset quarterly to an annual interest rate equal to the then-current three-month LIBOR rate plus 278 basis point payable quarterly.