Loans and Allowance for Credit Losses - Summary of Aging Analysis of Modifications (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	$ 18,797	$ 16,702
Current | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	8,694	16,702
30-59 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	2,105	0
60-89 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	7,998	0
90+ Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	0	0
Commercial Loans | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	8,579	15,849
Commercial Loans | Commercial real estate | Current | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	8,579	15,849
Commercial Loans | Commercial real estate | 30-59 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	0	0
Commercial Loans | Commercial real estate | 60-89 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	0	0
Commercial Loans | Commercial real estate | 90+ Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	0	0
Commercial Loans | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	10,103	594
Commercial Loans | Commercial and industrial | Current | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	0	594
Commercial Loans | Commercial and industrial | 30-59 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	2,105	0
Commercial Loans | Commercial and industrial | 60-89 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	7,998	0
Commercial Loans | Commercial and industrial | 90+ Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	0	0
Business banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	115
Business banking | Current | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	115
Business banking | 30-59 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	0
Business banking | 60-89 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	0
Business banking | 90+ Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months	$ 0
Consumer Loans | Consumer real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months		259
Consumer Loans | Consumer real estate | Current | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months		259
Consumer Loans | Consumer real estate | 30-59 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months		0
Consumer Loans | Consumer real estate | 60-89 Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months		0
Consumer Loans | Consumer real estate | 90+ Days Past Due | Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, modified, after 12 months		$ 0