Shareholders' Equity - Changes in Balances of Component of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 1,661,847	$ 1,492,268
Other comprehensive income (loss) before reclassification	(11,138)	30,726
Amounts reclassified from accumulated other comprehensive income (loss)	3,707	2,296
Other comprehensive income (loss), net of tax amount	(7,431)	33,022
Balance	1,682,599	1,562,099
Securities Available for Sale and Transferred Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(204,670)	(254,442)
Other comprehensive income (loss) before reclassification	832	26,024
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Other comprehensive income (loss), net of tax amount	832	26,024
Balance	(203,838)	(228,418)
Defined Benefit Pension Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(6,075)	(5,792)
Other comprehensive income (loss) before reclassification	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	92	98
Other comprehensive income (loss), net of tax amount	92	98
Balance	(5,983)	(5,694)
Cash Flow Hedge Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(8,978)	(15,169)
Other comprehensive income (loss) before reclassification	(11,970)	4,702
Amounts reclassified from accumulated other comprehensive income (loss)	3,615	2,198
Other comprehensive income (loss), net of tax amount	(8,355)	6,900
Balance	(17,333)	(8,269)
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(219,723)	(275,403)
Balance	$ (227,154)	$ (242,381)