Allowance for Credit Losses (Changes in Allowance for Credit Losses) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
LOANS
Balance at Beginning of Period	$ 161,100,000	$ 167,100,000	$ 164,300,000	$ 168,000,000.0	$ 168,000,000.0
Charge-Offs	(200,000)	(100,000)	(600,000)	(400,000)	(3,900,000)
Recoveries	600,000	400,000	900,000	900,000
Net Recoveries (Charge-Offs)	400,000	300,000	300,000	500,000
Provision for Credit Losses	(600,000)	13,100,000	(3,700,000)	12,000,000.0
Balance at End of Period	160,900,000	180,500,000	160,900,000	180,500,000	164,300,000
UNDRAWN LOAN COMMITMENTS AND STANDBY LETTERS OF CREDIT
Balance at Beginning of Period	25,500,000	32,800,000	23,300,000	30,400,000	30,400,000
Charge-Offs	0	0	0	0
Recoveries	0	0	0	0
Net Recoveries (Charge-Offs)	0	0	0	0
Provision for Credit Losses	(3,600,000)	1,900,000	(1,400,000)	4,300,000
Balance at End of Period	21,900,000	34,700,000	21,900,000	34,700,000	23,300,000
HELD TO MATURITY DEBT SECURITIES
Balance at Beginning of Period	7,700,000	6,700,000	9,300,000	6,500,000	6,500,000
Charge-Offs	0	0	0	0
Recoveries	0	0	0	0
Net Recoveries (Charge-Offs)	0	0	0	0
Provision for Credit Losses	(1,100,000)	200,000	(2,700,000)	400,000
Balance at End of Period	6,600,000	6,900,000	6,600,000	6,900,000	9,300,000
OTHER FINANCIAL ASSETS
Balance at Beginning of Period	900,000	700,000	1,400,000	1,000,000.0	1,000,000.0
Charge-Offs	0	0	0	0
Recoveries	0	0	0	0
Net Recoveries (Charge-Offs)	0	0	0	0
Provision for Credit Losses	0	400,000	(500,000)	100,000
Balance at End of Period	900,000	1,100,000	900,000	1,100,000	1,400,000
TOTAL
Balance at Beginning of Period	195,200,000	207,300,000	198,300,000	205,900,000	205,900,000
Charge-Offs	(200,000)	(100,000)	(600,000)	(400,000)
Recoveries	600,000	400,000	900,000	900,000
Net Recoveries (Charge-Offs)	400,000	300,000	300,000	500,000
Provision for credit losses	(5,300,000)	15,600,000	(8,300,000)	16,800,000
Balance at End of Period	190,300,000	223,200,000	190,300,000	223,200,000	198,300,000
TOTAL	190,300,000	223,200,000	190,300,000	223,200,000	$ 198,300,000
Provision for credit losses	$ 0	$ 900,000	$ 0	$ 700,000