Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income per consolidated statements of income	$ 45,037	$ 34,284	$ 95,337	$ 63,495
Net unrealized gains (losses) on available for sale securities and transferred securities:
Net unrealized holding gains (losses) arising during the period	(14,723)	(33,397)	8,407	(150,150)
Change in net unrealized holding loss on securities transferred to held to maturity	2,955	(25,338)	5,849	(24,938)
Reclassification adjustments for changes realized in net income:
Net change in prior service costs	20	21	41	41
Recognized net loss due to lump sum settlement	0	0	19	0
Change in net actuarial loss	52	228	110	465
Derivatives:
Change in the accumulated gain (loss) on effective cash flow hedge derivatives	(14,625)	0	(9,923)	0
Reclassification adjustment for (gain) loss realized in net income	2,998	0	5,196	0
Other comprehensive income (loss), net of tax	(23,323)	(58,486)	9,699	(174,582)
Comprehensive income (loss)	$ 21,714	$ (24,202)	$ 105,036	$ (111,087)