Consolidated Statements of Comprehensive Income - 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	$ 79,607	$ 69,989	$ 147,920	$ 134,277
Other Comprehensive Income/(Loss), net of tax:
Unrealized gains (losses) on securities	(31,219)	(88,352)	1,422	(242,211)
Reclassification adjustment for securities net change included in net income	(3)	6	14	21
Amortization of net unrealized gains (losses) on AFS securities transferred to HTM	1,501	(48,113)	2,979	(47,677)
Net unrealized gains (losses) on AFS investment securities	(29,721)	(136,459)	4,415	(289,867)
Net unrealized holding losses arising during the period	(5,586)	(8,586)	(12,406)	(39,962)
Reclassification adjustment for net change realized in net income	7,010	(335)	14,153	(1,842)
Net unrealized gains (losses) on interest rate derivatives used in cash flow hedges	1,424	(8,921)	1,747	(41,804)
Amortization of net unrecognized pension and postretirement items	3	25	28	50
Other Comprehensive Income (Loss)	(28,294)	(145,355)	6,190	(331,621)
Total Comprehensive Income (Loss)	$ 51,313	$ (75,366)	$ 154,110	$ (197,344)