For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2026	Dec. 31, 2025	Mar. 31, 2026	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Loss Contingencies [Line Items]
Conditional commitments	$ 52.0	$ 49.6	$ 53.3	$ 39.2	$ 35.1	$ 39.5
Other conditional commitments	$ 46.0	$ 21.0
Percentage of CRE loans occupied by owners	13.00%	14.00%
Commercial and industrial \| Loans Receivable \| Credit Concentration Risk
Loss Contingencies [Line Items]
Percent of commercial real estate related loans	49.00%	48.00%
Commercial Real Estate Portfolio Segment \| Loans Receivable \| Credit Concentration Risk
Loss Contingencies [Line Items]
Percent of commercial real estate related loans	26.00%	27.00%
Unfunded Loan Commitment
Loss Contingencies [Line Items]
Conditional commitments	$ 52.0	$ 49.6