Consolidated Statements of Comprehensive Income (Loss) (unaudited) - 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	$ 155,036	$ 114,985	$ 301,636	$ 87,399
Change in debt securities available-for-sale:
Unrealized holding gains (losses) for the period	(120,159)	(304,514)	(95,435)	(733,984)
Reclassification for securities transferred to held-to-maturity	0	143,310	0	165,473
Reclassification adjustment for securities (gains) losses realized in income	(17)	85	5,199	(257)
Income tax effect	30,043	38,408	31,189	134,643
Unrealized gains (losses) on available-for-sale securities	(90,133)	(122,711)	(59,047)	(434,125)
Change in securities held-to-maturity:
Adjustment for securities transferred from available-for-sale	0	(143,310)	0	(165,473)
Amortization of unrealized losses on securities transferred     from available-for-sale	5,122	3,692	10,951	4,002
Income tax effect	(1,300)	34,146	(1,431)	39,272
Changes from securities held-to-maturity	3,822	(105,472)	9,520	(122,199)
Change in hedges:
Net unrealized derivative gains (losses) on hedges	13,272	(3,418)	61,121	(12,924)
Reclassification adjustment for (gains) losses realized in net income	(32,112)	(219)	(24,820)	(888)
Income tax effect	4,872	894	(8,848)	3,394
Changes from hedges	(13,968)	(2,743)	27,453	(10,418)
Change in defined benefit pension plans:
Amortization of net (gains) losses recognized in income	6	(10)	(182)	(21)
Income tax effect	(2)	2	45	5
Changes from defined benefit pension plans	4	(8)	(137)	(16)
Other comprehensive income (loss), net of tax	(100,275)	(230,934)	(22,211)	(566,758)
Comprehensive income (loss)	$ 54,761	$ (115,949)	$ 279,425	$ (479,359)