Borrowed Funds - Components of Short-Term and Long-Term Debt (Parenthetical) (Detail)	Jun. 30, 2024	Dec. 31, 2023
Federal Home Loan Bank 5.51% and 5.04% [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	5.51%	5.04%
Federal Reserve Bank Term Funding Program 4.76% and 4.83% [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	4.76%	4.83%
Marquette Capital Trust I Subordinated Debentures 6.92% [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	6.92%	6.92%
Marquette Capital Trust II Subordinated Debentures 6.92% [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	6.92%	6.92%
Marquette Capital Trust III Subordinated Debentures 7.11% [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	7.11%	7.11%
Marquette Capital Trust IV Subordinated Debentures 7.20% [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	7.20%	7.20%
Subordinated notes 3.70%, net of issuance costs [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	3.70%	3.70%
Subordinated notes 6.25%, net issuance costs [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	6.25%	6.25%