Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net earnings (loss)	$ (1,237,574)	$ 468,636	$ 465,339
Goodwill impairment	1,470,000	0	0
Depreciation and amortization	44,839	39,115	35,168
Accretion (Amortization) of Discounts and Premiums, Investments	16,311	13,962	23,938
Customer related expense	14,753	18,726	22,506
Operating Lease, Right-of-Use Asset, Amortization	29,432	29,393	0
Provision For Losses On Foreclosed Assets	267	78	74
Gain on sale of foreclosed assets, net	(495)	(3,689)	(609)
Provision for credit losses	339,000	22,000	45,000
Gain on sale of loans and leases, net	(2,139)	(1,114)	(4,675)
Loss (gain) on sale of premises and equipment	346	599	(20)
Gain on sale of securities, net	(13,171)	(25,445)	(8,176)
Gain (Loss) on Sale of Insurance Block	0	0	(1,338)
Unrealized loss (gain) on derivatives and foreign currencies, net	66	(228)	(325)
Earned stock compensation	24,363	26,815	29,768
Decrease (increase) in other assets	(105,749)	30,261	24,981
Decrease in accrued interest payable and other liabilities	(96,376)	(36,449)	(23,604)
Net cash provided by operating activities	483,873	582,660	608,027
Cash flows from investing activities:
Net increase in loans and leases	(463,643)	(1,005,478)	(1,209,986)
Proceeds from sales of loans and leases	128,138	102,573	646,587
Proceeds from maturities and paydowns of securities available-for-sale	439,473	325,863	290,177
Proceeds from sales of securities available-for-sale	173,425	1,584,860	571,800
Purchases of securities available-for-sale	(1,924,917)	(1,569,421)	(1,180,545)
Net redemptions (purchases) of Federal Home Loan Bank stock	23,674	(8,821)	(11,313)
Proceeds from sales of foreclosed assets	1,396	8,590	13,479
Purchases of premises and equipment, net	(12,529)	(15,104)	(12,385)
Proceeds from sales of premises and equipment	8	73	57
Proceeds from Life Insurance Policy	761	555	3,546
Net increase in equipment leased to others under operating leases	(46,765)	(54,996)	(28,610)
Net cash used in investing activities	(1,680,979)	(631,306)	(917,193)
Cash flows from financing activities:
Net increase (decrease) in noninterest-bearing deposits	1,952,116	(643,530)	(615,263)
Net increase in interest-bearing deposits	3,757,152	1,008,152	624,094
Net (decrease) increase in borrowings	(1,754,008)	387,894	903,772
Net decrease in subordinated debentures		0	(12,372)
Common stock repurchased and restricted stock surrendered	(75,369)	(162,965)	(315,542)
Cash dividends paid, net	(159,748)	(289,048)	(288,193)
Net cash provided by financing activities	3,720,143	300,503	296,496
Net increase (decrease) in cash and cash equivalents	2,523,037	251,857	(12,670)
Cash and cash equivalents, beginning of year	637,624	385,767	398,437
Cash and cash equivalents, end of year	3,160,661	637,624	385,767
Supplemental disclosures of cash flow information:
Cash paid for interest	99,605	200,463	119,042
Cash paid for income taxes	114,235	123,533	98,575
Real Estate Owned, Transfer to Real Estate Owned	14,755	120
Loans transferred to foreclosed assets		120	16,914
Transfer of Portfolio Loans and Leases to Held-for-sale	0	25,124	0
Parent [Member]
Cash flows from operating activities:
Earned stock compensation		26,815	29,768
Decrease (increase) in other assets	$ (29,568)	(35,510)	(36,362)
Cash flows from financing activities:
Common stock repurchased and restricted stock surrendered		(162,965)	(315,542)
Cash dividends paid, net		$ (289,048)	$ (288,193)