Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 138,027	$ 65,606
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(9,000)	63,600
Depreciation and amortization of premises and equipment	13,775	14,331
Amortization of TCI	14,002	15,237
Net amortization of investment securities premiums	7,546	5,599
Investment securities gains, net	(33,511)	(3,051)
Gain on sales of mortgage loans held for sale	(14,094)	(22,728)
Proceeds from sales of mortgage loans held for sale	554,406	584,924
Originations of mortgage loans held for sale	(498,350)	(601,783)
Amortization of intangible assets	293	264
Amortization of issuance costs and discounts on long-term borrowings	1,378	543
Debt extinguishment costs	32,575	2,878
Stock-based compensation	4,000	3,530
Other changes, net	22,537	(161,412)
Total adjustments	95,557	(98,068)
Net cash provided by (used in) operating activities	233,584	(32,462)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of AFS securities	125,811	187,819
Proceeds from principal repayments and maturities of AFS securities	246,740	147,551
Proceeds from principal repayments and maturities of HTM securities	58,470	40,374
Purchase of AFS securities	(766,574)	(418,395)
Purchase of HTM securities	(227,687)	0
Sale of Visa Shares	33,962	0
Sale of FRB and FHLB stock	29,498	6,380
Net decrease (increase) in loans	300,929	(1,882,433)
Net purchases of premises and equipment	(10,648)	(13,881)
Net cash paid for acquisition	292	0
Net change in tax credit investments	(8,065)	(4,873)
Net cash used in investing activities	(217,272)	(1,937,458)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in demand and savings deposits	1,234,732	2,678,900
Net decrease in time deposits	(349,627)	(188,604)
Net decrease in short-term borrowings	(96,317)	(310,690)
Proceeds from long-term borrowings	620	495,898
Repayments of long-term borrowings	(703,624)	(85,893)
Net proceeds from issuance of common stock	2,715	3,198
Dividends paid	(48,584)	(42,333)
Acquisition of treasury stock	0	(39,748)
Net cash provided by financing activities	39,915	2,510,728
Net Increase in Cash and Cash Equivalents	56,227	540,808
Cash and Cash Equivalents at Beginning of Period	1,847,832	517,791
Cash and Cash Equivalents at End of Period	1,904,059	1,058,599
Cash paid during the period for:
Interest	37,805	63,837
Income taxes	8,127	11,051
Supplemental Schedule of Certain Noncash Activities:
Transfer of AFS securities to HTM securities	$ 376,165	$ 0