Loans and Leases Receivable and Allowance for Credit Losses - Summary of Amortized Cost of Loans and Leases on Nonaccrual Status (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Impaired [Line Items]
Nonaccrual loans with no related allowance	$ 40,862	$ 13,084
Nonaccrual loans with related allowance	11,177	6,937
Total nonaccrual loans	52,039	20,021
Multi-family
Financing Receivable, Impaired [Line Items]
Nonaccrual loans with no related allowance	18,800	4,117
Nonaccrual loans with related allowance	2,928	0
Total nonaccrual loans	21,728	4,117
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Nonaccrual loans with no related allowance	6,384	3,083
Nonaccrual loans with related allowance	2,069	1,448
Total nonaccrual loans	8,453	4,531
Commercial real estate owner occupied
Financing Receivable, Impaired [Line Items]
Nonaccrual loans with no related allowance	3,411	1,109
Nonaccrual loans with related allowance	0	854
Total nonaccrual loans	3,411	1,963
Commercial real estate non-owner occupied
Financing Receivable, Impaired [Line Items]
Nonaccrual loans with no related allowance	2,356	76
Nonaccrual loans with related allowance	0	0
Total nonaccrual loans	2,356	76
Residential real estate
Financing Receivable, Impaired [Line Items]
Nonaccrual loans with no related allowance	9,911	4,559
Nonaccrual loans with related allowance	0	1,569
Total nonaccrual loans	9,911	6,128
Manufactured housing
Financing Receivable, Impaired [Line Items]
Nonaccrual loans with no related allowance	0	0
Nonaccrual loans with related allowance	2,969	1,655
Total nonaccrual loans	2,969	1,655
Installment
Financing Receivable, Impaired [Line Items]
Nonaccrual loans with no related allowance	0	140
Nonaccrual loans with related allowance	3,211	1,411
Total nonaccrual loans	$ 3,211	$ 1,551