Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net income	$ 118,782	$ 151,995	$ 154,885
Securities available for sale:
Unrealized net holding gains (losses) arising during the period, gross	22,987	(209,212)	(37,432)
Tax effect	(5,746)	52,303	9,358
Unrealized net holding gains (losses) arising during the period, net	17,241	(156,909)	(28,074)
Reclassification adjustment for net losses in net income, gross	9,450	0	0
Tax effect	(2,363)	0	0
Reclassification adjustment for net losses in net income, net	7,087	0	0
Amortization of unrealized net gains for the reclassification of available for sale securities to held to maturity, gross	427	513	577
Tax effect	(107)	(128)	(145)
Amortization of unrealized net gains for the reclassification of available for sale securities to held to maturity, net	320	385	432
Total securities available for sale, net	24,648	(156,524)	(27,642)
Cash flow hedges:
Reclassification of net unrealized losses on cash flow hedges to interest expense, gross	0	0	21
Tax effect	0	0	(5)
Reclassification of net unrealized losses on cash flow hedges to interest expense, net	0	0	16
Total cash flow hedges, net	0	0	16
Pension and other benefits:
Amortization of prior service cost and actuarial losses, gross	2,640	737	1,373
Tax effect	(660)	(184)	(343)
Amortization of prior service cost and actuarial losses, net	1,980	553	1,030
Decrease (increase) in unrecognized actuarial loss, gross	3,296	(14,292)	3,780
Tax effect	(824)	3,573	(945)
Decrease (increase) in unrecognized actuarial loss, net	2,472	(10,719)	2,835
Total pension and other benefits, net	4,452	(10,166)	3,865
Total other comprehensive income (loss)	29,100	(166,690)	(23,761)
Comprehensive income (loss)	$ 147,882	$ (14,695)	$ 131,124