Borrowed Funds - Components of Long-Term Debt (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2021
Marquette Capital Trust I Subordinated Debentures 1.45% due 2036 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	1.45%
Debt instrument, maturity year	2036
Marquette Capital Trust II Subordinated Debentures 1.45% due 2036 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	1.45%
Debt instrument, maturity year	2036
Marquette Capital Trust III Subordinated Debentures 1.72% due 2036 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	1.72%
Debt instrument, maturity year	2036
Marquette Capital Trust IV Subordinated Debentures 1.80% due 2036 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	1.80%
Debt instrument, maturity year	2036
Subordinated notes 3.70% due 2030, net of issuance costs [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	3.70%
Debt instrument, maturity year	2030