Investment Securities - Unrealized Gross Losses and Fair Values of Securities in a Continuous Loss Position (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2025 USD ($) security	Dec. 31, 2024 USD ($) security
Securities in the available-for-sale portfolio in a continuous loss position
Number of individual securities in a continuous loss position | security	154	159
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	$ (2,633,000)	$ (4,775,000)
12 Months or More Unrealized Losses	(230,348,000)	(259,563,000)
Total Unrealized Losses	(232,981,000)	(264,338,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months Fair Value	262,940,000	277,688,000
12 Months or More Fair Value	1,410,806,000	1,443,285,000
Total Fair Value	$ 1,673,746,000	$ 1,720,973,000
Number of securities with intent to sell	0	0
Credit losses recognized on securities	$ 0	$ 0
Allowance for credit losses, investment securities	$ 0	$ 0
Investment securities comprised of collateralized loan obligations rated AA or better and obligations issued by local state and political subdivisions rated AA or better	4.00%	4.00%
Government agency debt securities
Time in Continuous Loss, Unrealized Losses
12 Months or More Unrealized Losses		$ (23,000)
Total Unrealized Losses		(23,000)
Time in Continuous Loss, Fair Value
12 Months or More Fair Value		8,147,000
Total Fair Value		8,147,000
Residential - Government agency
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses		(154,000)
12 Months or More Unrealized Losses	$ (1,305,000)	(1,460,000)
Total Unrealized Losses	(1,305,000)	(1,614,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months Fair Value		27,127,000
12 Months or More Fair Value	8,718,000	8,732,000
Total Fair Value	8,718,000	35,859,000
Residential - Government-sponsored enterprises
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(1,512,000)	(2,997,000)
12 Months or More Unrealized Losses	(85,165,000)	(99,726,000)
Total Unrealized Losses	(86,677,000)	(102,723,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months Fair Value	114,923,000	116,084,000
12 Months or More Fair Value	606,556,000	622,029,000
Total Fair Value	721,479,000	738,113,000
Commercial - Government agency
Time in Continuous Loss, Unrealized Losses
12 Months or More Unrealized Losses	(50,373,000)	(53,223,000)
Total Unrealized Losses	(50,373,000)	(53,223,000)
Time in Continuous Loss, Fair Value
12 Months or More Fair Value	195,766,000	196,125,000
Total Fair Value	195,766,000	196,125,000
Commercial - Government-sponsored enterprises
Time in Continuous Loss, Unrealized Losses
12 Months or More Unrealized Losses	(2,368,000)	(3,107,000)
Total Unrealized Losses	(2,368,000)	(3,107,000)
Time in Continuous Loss, Fair Value
12 Months or More Fair Value	44,012,000	44,908,000
Total Fair Value	44,012,000	44,908,000
Government agency
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(937,000)	(712,000)
12 Months or More Unrealized Losses	(48,158,000)	(54,202,000)
Total Unrealized Losses	(49,095,000)	(54,914,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months Fair Value	75,714,000	76,968,000
12 Months or More Fair Value	306,599,000	310,171,000
Total Fair Value	382,313,000	387,139,000
Government-sponsored enterprises
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(165,000)	(912,000)
12 Months or More Unrealized Losses	(42,979,000)	(47,822,000)
Total Unrealized Losses	(43,144,000)	(48,734,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months Fair Value	56,582,000	57,509,000
12 Months or More Fair Value	249,155,000	253,173,000
Total Fair Value	305,737,000	$ 310,682,000
Collateralized loan obligations
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(19,000)
Total Unrealized Losses	(19,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months Fair Value	15,721,000
Total Fair Value	$ 15,721,000