Securities - Amortized Cost and Fair Value (Details) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026 USD ($) security item	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($) security item	Jun. 30, 2025 USD ($)	Dec. 31, 2025 USD ($)
Securities Available-for-Sale
Amortized Cost	$ 1,088,379		$ 1,088,379		$ 1,133,592
Gross Unrealized Gains	1,464		1,464		3,753
Gross Unrealized Losses	(49,083)		(49,083)		(46,822)
Fair Value	1,040,760		1,040,760		1,090,523
Accrued interest receivable	6,800		6,800		6,900
FHLB and FRB Stock
FHLBC stock	19,400		19,400		11,300
FRBC stock	$ 20,700		$ 20,700		20,700
Other disclosures
Number of securities issued from originators \| security	0		0
Number of originators \| item	1		1
Minimum percentage of securities investment			10.00%
Proceeds from sales of securities	$ 0	$ 0	$ 0	$ 0
Securities pledged to secure deposits and for other purposes	663,700		663,700		679,500
U.S. Treasury
Securities Available-for-Sale
Amortized Cost	144,392		144,392		164,296
Gross Unrealized Gains	183		183		1,564
Gross Unrealized Losses	(188)		(188)
Fair Value	144,387		144,387		165,860
U.S. government agencies
Securities Available-for-Sale
Amortized Cost	68,861		68,861		29,421
Gross Unrealized Losses	(457)		(457)		(245)
Fair Value	68,404		68,404		29,176
U.S. government agencies mortgage-backed
Securities Available-for-Sale
Amortized Cost	88,663		88,663		95,899
Gross Unrealized Losses	(7,427)		(7,427)		(7,119)
Fair Value	81,236		81,236		88,780
States and political subdivisions
Securities Available-for-Sale
Amortized Cost	205,386		205,386		213,366
Gross Unrealized Gains	230		230		450
Gross Unrealized Losses	(7,671)		(7,671)		(7,441)
Fair Value	197,945		197,945		206,375
Collateralized mortgage obligations
Securities Available-for-Sale
Amortized Cost	374,483		374,483		388,774
Gross Unrealized Gains	509		509		1,102
Gross Unrealized Losses	(31,931)		(31,931)		(30,571)
Fair Value	343,061		343,061		359,305
Asset-backed Securities
Securities Available-for-Sale
Amortized Cost	40,128		40,128		46,600
Gross Unrealized Gains	327		327		423
Gross Unrealized Losses	(1,330)		(1,330)		(1,207)
Fair Value	39,125		39,125		45,816
Collateralized loan obligations.
Securities Available-for-Sale
Amortized Cost	165,752		165,752		194,552
Gross Unrealized Gains	183		183		151
Gross Unrealized Losses	(79)		(79)		(239)
Fair Value	165,856		165,856		194,464
Equity Securities
Securities Available-for-Sale
Amortized Cost	714		714		684
Gross Unrealized Gains	32		32		63
Fair Value	$ 746		$ 746		$ 747

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Represents the number of originators that the company has invested over 10 % of its stockholders equity.

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Represents the number of securities issued from originators.

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Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

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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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Amount, before tax, of unrealized loss 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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Amortized cost excluding accrued interest, before allowance for credit loss, of 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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Amount excluding accrued interest, of 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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Amount of restricted 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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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Amount of cash inflow from sale of 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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