Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 348,715	$ 336,752	$ 420,300
Available for sale securities:
Unrealized gains (losses) arising during the period	109,221	(548,193)	(124,970)
Income tax (expense) benefit related to unrealized gains (losses)	(28,411)	140,995	32,142
Reclassification adjustment for net realized gains in earnings	(13)	(2)	(8)
Income tax expense related to realized gains	3	1	2
Net change in unrealized gains (losses) for available for sale securities	80,800	(407,199)	(92,834)
Junior subordinated debentures, at fair value:
Unrealized gains (losses) arising during the period	7,866	(28,842)	(37,899)
Income tax (expense) benefit related to unrealized gains (losses)	(2,045)	7,418	9,747
Net change in unrealized gains (losses) for junior subordinated debentures, at fair value	5,821	(21,424)	(28,152)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent [Abstract]
Amortization of unrecognized net actuarial gain included in net periodic pension cost	(136)	0	0
Income tax expense related to unrecognized actuarial loss	(35)	0	0
Net change in pension plan liability adjustment	(101)	0	0
Other comprehensive income (loss), net of tax	86,722	(428,623)	(120,986)
Comprehensive income (loss)	$ 435,437	$ (91,871)	$ 299,314