Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			$ (74,416)				$ (74,416)
Debt Securities, Available-for-sale, Realized Loss	$ 0			$ 0			0	$ (197)
Amortization of Net Unrealized Losses on Available-for-Sale Securities Transfered to Held-to-maturity Securities	(1,992)			(2,147)			(5,978)	(6,329)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	(825)			25,609			7,707	(639)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	1,440			4,705			3,995	14,297
Labor and Related Expense	135,703			121,036			386,593	362,012
Other Comprehensive Income (Loss), Net of Tax	(1,680)	$ 20,847	39,272	107,466	$ (9,333)	$ (38,785)	58,439	59,348
Ending Balance	(15,977)						(15,977)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(6,109)		(48,993)	(176,139)		(148,641)	(48,993)	(148,641)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(5,178)			90,858			47,970	49,844
Debt Securities, Available-for-sale, Realized Loss								197
Amortization of Net Unrealized Losses on Available-for-Sale Securities Transfered to Held-to-maturity Securities	1,992			2,147			5,978	6,329
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	0			0			0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	0			0			0	0
Labor and Related Expense	0			0			0	0
Other Expenses	0			0			0	0
Other Comprehensive Income (Loss), Tax	795			(23,198)			(13,456)	(14,060)
Other Comprehensive Income (Loss), Net of Tax	(2,392)			69,807			40,492	42,309
Ending Balance	(8,501)	(6,109)		(106,332)	(176,139)		(8,501)	(106,332)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	12,487		(1,268)	(15,768)		3,080	(1,268)	3,080
Other Comprehensive Income (Loss), before Reclassifications, before Tax	0			0			0	0
Debt Securities, Available-for-sale, Realized Loss								0
Amortization of Net Unrealized Losses on Available-for-Sale Securities Transfered to Held-to-maturity Securities	0			0			0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	(825)			25,609			7,707	(639)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	1,440			4,705			3,995	14,297
Labor and Related Expense	0			0			0	0
Other Expenses	0			0			0	0
Other Comprehensive Income (Loss), Tax	148			7,405			2,816	5,213
Other Comprehensive Income (Loss), Net of Tax	763			37,718			14,518	18,871
Ending Balance	13,249	12,487		21,951	(15,768)		13,249	21,951
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(20,674)		(24,154)	(27,307)		(25,535)	(24,154)	(25,535)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	0			0			4,770	0
Debt Securities, Available-for-sale, Realized Loss								0
Amortization of Net Unrealized Losses on Available-for-Sale Securities Transfered to Held-to-maturity Securities	0			0			0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	0			0			0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	0			0			0	0
Labor and Related Expense	(63)			(73)			189	217
Other Expenses	(4)			(7)			(12)	(21)
Other Comprehensive Income (Loss), Tax	17			20			(1,140)	(1,594)
Other Comprehensive Income (Loss), Net of Tax	(51)			(60)			3,429	(1,832)
Ending Balance	(20,725)	(20,674)		(27,367)	(27,307)		(20,725)	(27,367)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(14,297)		(74,416)	(219,214)		(171,096)	(74,416)	(171,096)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(5,178)			90,858			52,741	49,844
Debt Securities, Available-for-sale, Realized Loss								197
Amortization of Net Unrealized Losses on Available-for-Sale Securities Transfered to Held-to-maturity Securities	1,992			2,147			5,978	6,329
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	(825)			25,609			7,707	(639)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	1,440			4,705			3,995	14,297
Labor and Related Expense	(63)			(73)			189	217
Other Expenses	(4)			(7)			(12)	(21)
Other Comprehensive Income (Loss), Tax	960			(15,773)			(11,780)	(10,440)
Other Comprehensive Income (Loss), Net of Tax	(1,680)	20,847	$ 39,272	107,466	(9,333)	$ (38,785)	58,439	59,348
Ending Balance	$ (15,977)	$ (14,297)		$ (111,748)	$ (219,214)		$ (15,977)	$ (111,748)