Consolidated Statements of Comprehensive Income (Loss) (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Consolidated Statements of Comprehensive Income (Loss) (unaudited) [Abstract]
Net income	$ 54,471	$ 38,097	$ 113,726	$ 104,636
Securities available for sale:
Unrealized net holding gains arising during the period, gross	13,800	49,019	55,569	45,283
Tax effect	(3,449)	(12,255)	(13,892)	(11,321)
Unrealized net holding gains arising during the period, net	10,351	36,764	41,677	33,962
Amortization of unrealized net gains for the reclassification of available for sale securities to held to maturity, gross	68	87	213	274
Tax effect	(17)	(21)	(53)	(68)
Amortization of unrealized net gains for the reclassification of available for sale securities to held to maturity, net	51	66	160	206
Total securities available for sale, net	10,402	36,830	41,837	34,168
Pension and other benefits:
Amortization of prior service cost and actuarial losses, gross	275	471	906	2,374
Tax effect	(69)	(118)	(227)	(594)
Amortization of prior service cost and actuarial losses, net	206	353	679	1,780
Decrease (increase) in unrecognized actuarial loss, gross	0	0	936	(1,000)
Tax effect	0	0	(234)	250
Decrease (increase) in unrecognized actuarial loss, net	0	0	702	(750)
Total pension and other benefits, net	206	353	1,381	1,030
Total other comprehensive income	10,608	37,183	43,218	35,198
Comprehensive income	$ 65,079	$ 75,280	$ 156,944	$ 139,834