Other Comprehensive Income (Loss) - Components of OCI (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Before Tax
Total other comprehensive income (loss)	$ (115,209)	$ 23,184	$ (137,070)	$ 77,295
Tax Effect
Total	32,202	(6,657)	38,313	(29,183)
After Tax
Total other comprehensive (loss) income	(83,007)	16,527	(98,757)	48,112
Unrealized gains and losses on available for sale debt securities:
Before Tax
Net unrealized gains (losses) arising during the period	(120,083)	27,957	(149,589)	88,132
Reclassification adjustment for gains included in net income	0	0	806	(87)
Total other comprehensive income (loss)	(120,083)	27,957	(148,783)	88,045
Tax Effect
Net unrealized gains (losses) arising during the period	33,565	(8,009)	41,811	(32,252)
Reclassification adjustment for (gains) losses on securities sales included in net income	0	0	(224)	24
Total	33,565	(8,009)	41,587	(32,228)
After Tax
Net unrealized gains (losses) arising during the period	(86,518)	19,948	(107,778)	55,880
Reclassification adjustment for (gains) losses on securities sales included in net income	0	0	582	(63)
Total other comprehensive (loss) income	(86,518)	19,948	(107,196)	55,817
Unrealized gains and losses on derivatives (cash flow hedges):
Before Tax
Net unrealized gains (losses) arising during the period	5,192	615	12,381	(214)
Reclassification adjustment for gains included in net income	(131)	(2,056)	(270)	(6,285)
Total other comprehensive income (loss)	5,061	(1,441)	12,111	(6,499)
Tax Effect
Net unrealized gains (losses) arising during the period	(1,451)	(174)	(3,460)	61
Reclassification adjustment for (gains) losses on securities sales included in net income	36	582	75	1,780
Total	(1,415)	408	(3,385)	1,841
After Tax
Net unrealized gains (losses) arising during the period	3,741	441	8,921	(153)
Reclassification adjustment for (gains) losses on securities sales included in net income	(95)	(1,474)	(195)	(4,505)
Total other comprehensive (loss) income	3,646	(1,033)	8,726	(4,658)
Post- Retirement Obligations
Before Tax
Total other comprehensive income (loss)	(187)	(3,332)	(398)	(4,251)
Tax Effect
Total	52	944	111	1,204
After Tax
Total other comprehensive (loss) income	$ (135)	$ (2,388)	$ (287)	$ (3,047)

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