Other Comprehensive Income (Loss) - Other Comprehensive Income Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	$ 715,067	$ 663,558	$ 558,393
Other Comprehensive Income (Loss) Before Reclassification	55,530	(30,511)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	0	27,107
Total Other Comprehensive Income (Loss)	55,530	(3,404)	46,378
Ending Balance	1,162,325	715,067	663,558
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(220,464)	(217,060)	(263,438)
Total Other Comprehensive Income (Loss)	55,530	(3,404)	46,378
Ending Balance	(164,934)	(220,464)	(217,060)
Unrealized Gains and Losses on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(219,950)	(216,546)
Other Comprehensive Income (Loss) Before Reclassification	55,530	(30,511)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	0	27,107
Total Other Comprehensive Income (Loss)	55,530	(3,404)
Ending Balance	(164,420)	(219,950)	(216,546)
Postretirement Benefit Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(514)	(514)
Other Comprehensive Income (Loss) Before Reclassification	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	0	0
Total Other Comprehensive Income (Loss)	0	0
Ending Balance	$ (514)	$ (514)	$ (514)