Shareholders' Equity - Changes in Balances of Component of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 1,682,599	$ 1,562,099	$ 1,661,847	$ 1,492,268
Other comprehensive income (loss) before reclassification			(16,361)	4,333
Amounts reclassified from accumulated other comprehensive income (loss)			144,527	5,366
Other comprehensive income (loss), net of tax amount	135,597	(23,323)	128,166	9,699
Balance	1,879,141	1,571,193	1,879,141	1,571,193
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			(736)	14,256
Amounts reclassified from accumulated other comprehensive income (loss)			137,094	0
Other comprehensive income (loss), net of tax amount			136,358	14,256
Balance	(68,312)	(240,186)	(68,312)	(240,186)
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)			166	170
Other comprehensive income (loss), net of tax amount			166	170
Balance	(5,909)	(5,622)	(5,909)	(5,622)
Cash Flow Hedge Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			(8,978)	(15,169)
Other comprehensive income (loss) before reclassification			(15,625)	(9,923)
Amounts reclassified from accumulated other comprehensive income (loss)			7,267	5,196
Other comprehensive income (loss), net of tax amount			(8,358)	(4,727)
Balance	(17,336)	(19,896)	(17,336)	(19,896)
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(227,154)	(242,381)	(219,723)	(275,403)
Balance	$ (91,557)	$ (265,704)	$ (91,557)	$ (265,704)