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Securities - Amortized Cost and Fair Value of Securities Available for Sale (Details) - USD ($)	Sep. 30, 2025	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Allowance for credit loss	$ 0	$ 0
Amortized cost and fair value of securities available for sale
Amortized Cost	2,599,397,000	968,927,000
Gross Unrealized Gains	15,736,000	694,000
Gross Unrealized Losses	(102,483,000)	(138,608,000)
Fair Value	2,512,650,000	831,013,000
Obligations of states and political subdivisions
Amortized cost and fair value of securities available for sale
Amortized Cost	270,696,000	20,266,000
Gross Unrealized Gains	5,318,000	57,000
Gross Unrealized Losses	(2,365,000)	(2,269,000)
Fair Value	273,649,000	18,054,000
Other debt securities
Amortized cost and fair value of securities available for sale
Amortized Cost	364,473,000	130,175,000
Gross Unrealized Gains	871,000	440,000
Gross Unrealized Losses	(3,239,000)	(2,655,000)
Fair Value	362,105,000	127,960,000
Mortgage backed securities issued by U.S. Government agencies or sponsored enterprises | Residential mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	710,105,000	185,292,000
Gross Unrealized Gains	3,709,000	81,000
Gross Unrealized Losses	(17,508,000)	(24,468,000)
Fair Value	696,306,000	160,905,000
Mortgage backed securities issued by U.S. Government agencies or sponsored enterprises | Commercial mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	100,337,000	11,373,000
Gross Unrealized Gains	221,000	0
Gross Unrealized Losses	(799,000)	(751,000)
Fair Value	99,759,000	10,622,000
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises | Residential mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	739,005,000	475,311,000
Gross Unrealized Gains	2,978,000	75,000
Gross Unrealized Losses	(59,903,000)	(86,870,000)
Fair Value	682,080,000	388,516,000
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises | Commercial mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	414,781,000	146,510,000
Gross Unrealized Gains	2,639,000	41,000
Gross Unrealized Losses	(18,669,000)	(21,595,000)
Fair Value	$ 398,751,000	$ 124,956,000

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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