Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 135,845	$ 84,040	$ 255,184	$ 253,788
Available for sale securities:
Unrealized losses arising during the period	(333,993)	(186,336)	(334,298)	(575,781)
Income tax benefit related to unrealized losses	86,837	47,926	86,904	148,091
Reclassification adjustment for net realized gains in earnings	(4)	0	(4)	(2)
Income tax expense related to realized gains	1	0	1	1
Net change in unrealized losses for available for sale securities	(247,159)	(138,410)	(247,397)	(427,691)
Junior subordinated debentures, at fair value:
Unrealized losses arising during the period	(19,677)	(4,043)	(8,503)	(31,810)
Income tax benefit related to unrealized losses	5,116	1,040	2,211	8,182
Net change in unrealized losses for junior subordinated debentures, at fair value	(14,561)	(3,003)	(6,292)	(23,628)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent [Abstract]
Amortization of unrecognized net actuarial loss included in net periodic pension cost	72	0	168	0
Income tax expense related to unrecognized actuarial loss	(19)	0	(44)	0
Net change in pension plan liability adjustment	53	0	124	0
Other comprehensive loss, net of tax	(261,667)	(141,413)	(253,565)	(451,319)
Comprehensive (loss) income	$ (125,822)	$ (57,373)	$ 1,619	$ (197,531)