Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net earnings (loss)	$ 606,959	$ (1,237,574)	$ 468,636
Goodwill impairment	0	1,470,000	0
Depreciation and amortization	52,195	44,839	39,115
Amortization of net premiums on securities available-for-sale	44,197	16,311	13,962
Intangible asset amortization	12,734	14,753	18,726
Amortization of operating lease ROU assets	30,406	29,432	29,393
Provision for credit losses	(162,000)	339,000	22,000
Gain on sale of foreclosed assets, net	(406)	(495)	(3,689)
Provision for losses on foreclosed assets	14	267	78
Gain on sale of loans and leases, net	(1,733)	(2,139)	(1,114)
Loss on sale of premises and equipment	74	346	599
Gain on sale of securities, net	(1,615)	(13,171)	(25,445)
Gain on BOLI death benefits	(491)	0	0
Unrealized (gain) loss on derivatives and foreign currencies, net	(1,134)	66	(228)
(Increase) decrease in other assets	(97,181)	(105,749)	30,261
Decrease in accrued interest payable and other liabilities	(11,286)	(96,376)	(36,449)
Net cash provided by operating activities	502,956	483,873	582,660
Cash flows from investing activities:
Cash acquired in acquisitions, net of cash consideration paid	3,757,122	0	0
Net increase in loans and leases	(3,925,829)	(463,643)	(1,005,478)
Proceeds from sales of loans and leases	144,550	128,138	102,573
Proceeds from maturities and paydowns of securities available-for-sale	847,472	439,473	325,863
Proceeds from sales of securities available-for-sale	367,348	173,425	1,584,860
Purchases of securities available-for-sale	(6,863,950)	(1,924,917)	(1,569,421)
Net redemptions (purchases) of Federal Home Loan Bank stock	0	23,674	(8,821)
Proceeds from sales of foreclosed assets	2,638	1,396	8,590
Purchases of premises and equipment, net	(17,262)	(12,529)	(15,104)
Proceeds from sales of premises and equipment	95	8	73
Proceeds from BOLI death benefits	4,143	761	555
Net increase in equipment leased to others under operating leases	(30,786)	(46,765)	(54,996)
Net cash used in investing activities	(5,714,459)	(1,680,979)	(631,306)
Cash flows from financing activities:
Net increase (decrease) in noninterest-bearing deposits	3,726,157	1,952,116	(643,530)
Net increase in interest-bearing deposits	2,170,769	3,757,152	1,008,152
Net (decrease) increase in borrowings	(55,210)	(1,754,008)	387,894
Common stock repurchased and restricted stock surrendered	(8,505)	(75,369)	(162,965)
Cash dividends paid, net	(119,443)	(159,748)	(289,048)
Net cash provided by financing activities	6,108,076	3,720,143	300,503
Net increase in cash and cash equivalents	896,573	2,523,037	251,857
Cash and cash equivalents, beginning of year	3,160,661	637,624	385,767
Cash and cash equivalents, end of year	4,057,234	3,160,661	637,624
Supplemental disclosures of cash flow information:
Cash paid for interest	53,446	99,605	200,463
Cash paid for income taxes	136,015	114,235	123,533
Loans transferred to foreclosed assets	1,062	14,755	120
Transfers from loans held for investment to loans held for sale	25,554	0	25,124
Fair value of assets acquired	40,443,344	29,498,442
Liabilities assumed	36,443,714	25,903,491
Parent [Member]
Cash flows from operating activities:
Earned stock compensation	32,223	24,363	26,815
(Increase) decrease in other assets	(67,242)	(29,568)	(35,510)
Cash flows from financing activities:
Proceeds from subordinated notes offering, net	394,308	0	0
Common stock repurchased and restricted stock surrendered		(75,369)	(162,965)
Cash dividends paid, net		(159,748)	$ (289,048)
Supplemental disclosures of cash flow information:
Fair value of assets acquired	4,144,900	3,734,507
Liabilities assumed	$ 145,270	$ 139,556