Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2026

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis

Financial assets and financial liabilities measured at fair value on a recurring basis are as follows:

			Fair Value Measurements at Reporting Date Using
As of March 31, 2026	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Investment debt securities available-for-sale:
U.S. Treasury notes	$	237.5	$	—	$	237.5	$	—
State, county, and municipal securities	217.1			—	217.1			—
Obligations of U.S. government agencies	175.9			—	175.9			—
U.S. agency commercial mortgage-backed securities	839.9			—	839.9			—
U.S. agency residential mortgage-backed securities	2,223.1			—	2,223.1			—
U.S. agency collateralized mortgage obligations	880.9			—	880.9			—
Private mortgage-backed securities	168.5			—	168.5			—
Collateralized loan obligations	833.4			—	833.4			—
Corporate securities	140.3			—	140.3			—
Loans held for sale	4.7			—	4.7			—
Derivative assets:
Interest rate swap contracts	27.0			—	27.0			—
Derivative liabilities:
Interest rate swap contracts	76.8			—	76.8			—
Deferred compensation plan assets	21.4			21.4	—			—

			Fair Value Measurements at Reporting Date Using
As of December 31, 2025	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Investment debt securities available-for-sale:
U.S. Treasury notes	$	237.7	$	—	$	237.7	$	—
State, county and municipal securities	220.1			—	220.1			—
Obligations of U.S. government agencies	200.9			—	200.9			—
U.S. agency commercial mortgage-backed securities	856.7			—	856.7			—
U.S. agency residential mortgage-backed securities	1,770.1			—	1,770.1			—
U.S. agency collateralized mortgage obligations	922.7			—	922.7			—
Private mortgage-backed securities	174.4			—	174.4			—
Collateralized loan obligations	755.5			—	755.5			—
Corporate securities	150.0			—	150.0			—
Loans held for sale	1.1			—	1.1			—
Derivative assets:
Interest rate swap contracts	26.6			—	26.6			—
Derivative liabilities
Interest rate swap contracts	77.3			—	77.3			—
Deferred compensation plan assets	23.2			23.2	—			—

Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Non-Recurring Basis

The following table presents information about the Company’s assets and liabilities measured at fair value on a non-recurring basis with an adjustment during the period presented. The fair values may not be current as of the reporting date but represent fair values as of the most recent fair value change that occurred with the reporting period. Accordingly, carrying values may not equal the current fair value:

As of March 31, 2026	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Collateral-dependent loans	$	40.8	$	—	$	—	$	40.8
Long-lived assets to be disposed of by sale	1.4			—		—	1.4
As of December 31, 2025
Collateral-dependent loans	$	21.5	$	—	$	—	$	21.5
Long-lived assets to be disposed of by sale	1.3			—		—	1.3

Fair Value Inputs, Assets, Quantitative Information

The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis and for which the Company has utilized Level 3 inputs to determine fair values:

As of March 31, 2026	Fair Value		Valuation Technique	Unobservable Inputs	Range (Weighted Average)
Collateral-dependent loans	$	40.8	Appraisal	Appraisal adjustment	4%	-	100%	(24%)
Long-lived assets to be disposed of by sale	1.4		Appraisal	Appraisal adjustment	—	-	—	—
As of December 31, 2025
Collateral-dependent loans	$	21.5	Appraisal	Appraisal adjustment	2%	-	99%	(33%)
Long-lived assets to be disposed of by sale	1.3		Appraisal	Appraisal adjustment	—	-	—	—

Fair Value, by Balance Sheet Grouping

The estimated fair values of financial instruments that are reported in the Company’s consolidated balance sheets, and are segregated by the level of the valuation inputs within the fair value hierarchy that are utilized to measure fair value, are as follows:

					Fair Value Measurements at Reporting Date Using
As of March 31, 2026	Carrying Amount		Estimated Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Financial assets:
Cash and cash equivalents	$	1,208.7	$	1,208.7	$	1,208.7	$	—	$	—
Investment debt securities held-to-maturity	2,293.4		2,082.7		—		2,082.7		—
Accrued interest receivable	101.3		101.3		—		101.3		—
Mortgage servicing rights, net	22.5		33.1		—		—		33.1
Net loans held for investment	14,532.6		14,345.3		—		—		14,345.3
Total financial assets	$	18,158.5	$	17,771.1	$	1,208.7	$	2,184.0	$	14,378.4
Financial liabilities:
Total deposits, excluding time deposits	$	19,448.0	$	19,448.0	$	19,448.0	$	—	$	—
Time deposits	2,435.0		2,422.4		—		2,422.4		—
Securities sold under repurchase agreements	476.1		476.1		—		476.1		—
Accrued interest payable	33.1		33.1		—		33.1		—
Long-term debt	146.7		153.3		—		153.3		—
Subordinated debentures held by subsidiary trusts	149.9		139.1		—		139.1		—
Total financial liabilities	$	22,688.8	$	22,672.0	$	19,448.0	$	3,224.0	$	—

					Fair Value Measurements at Reporting Date Using
As of December 31, 2025	Carrying Amount		Estimated Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Financial assets:
Cash and cash equivalents	$	1,309.7	$	1,309.7	$	1,309.7	$	—	$	—
Investment debt securities held-to-maturity	2,342.1		2,136.6		—		2,136.6		—
Accrued interest receivable	102.6		102.6		—		102.6		—
Mortgage servicing rights, net	23.1		32.3		—		—		32.3
Net loans held for investment	15,010.2		14,769.1		—		—		14,769.1
Total financial assets	$	18,787.7	$	18,350.3	$	1,309.7	$	2,239.2	$	14,801.4
Financial liabilities:
Total deposits, excluding time deposits	$	19,450.0	$	19,450.0	$	19,450.0	$	—	$	—
Time deposits	2,638.3		2,629.2		—		2,629.2		—
Securities sold under repurchase agreements	479.6		479.6		—		479.6		—
Accrued interest payable	36.9		36.9		—		36.9		—
Long-term debt	146.3		153.4		—		153.4		—
Subordinated debentures held by subsidiary trusts	149.8		140.0		—		140.0		—
Total financial liabilities	$	22,900.9	$	22,889.1	$	19,450.0	$	3,439.1	$	—