Consolidated Statement of Cash Flows - Unaudited - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 655,185	$ 403,713
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	116,371	96,089
Amortization of premiums and accretion of discount, net	17,392	(17,974)
Stock compensation costs	24,047	22,201
Deferred income tax benefit (expense)	787	(91)
(Reversal of) provision for credit losses	(25,000)	186,313
Net gains on sales of loans	(6,601)	(1,443)
Gains on sales of AFS debt securities	(1,178)	(11,867)
Impairment on other real estate owned ("OREO") and other foreclosed assets	4,843	0
Net gains on sales of OREO and other foreclosed assets	(1,954)	0
Loans held-for-sale:
Originations and purchases	(9,323)	(53,911)
Proceeds from sales and paydowns/payoffs of loans originally classified as held-for-sale	11,337	50,339
Proceeds from distributions received from equity method investees	7,624	4,934
Net change in accrued interest receivable and other assets	(78,649)	(467,077)
Net change in accrued expenses and other liabilities	30,179	220,343
Other net operating activities	771	529
Total adjustments	90,646	28,385
Net cash provided by operating activities	745,831	432,098
CASH FLOWS FROM INVESTING ACTIVITIES
Investments in qualified affordable housing partnerships, tax credit and other investments	(141,882)	(102,190)
Interest-bearing deposits with banks	4,576	(503,187)
Resale agreements:
Proceeds from paydowns and maturities	698,274	400,000
Purchases	1,834,416	500,000
AFS debt securities:
Proceeds from sales	236,967	494,877
Proceeds from repayments, maturities and redemptions	1,346,839	1,532,411
Purchases	(5,884,389)	(3,167,863)
Loans held-for-investment:
Proceeds from sales of loans originally classified as held-for-investment	416,426	254,035
Purchases	(746,395)	(163,861)
Other changes in loans held-for-investment, net	1,798,011	2,764,867
Proceeds from sales of OREO and other foreclosed assets	28,560	0
Purchase of bank-owned life insurance	(150,000)	0
Proceeds from distributions received from equity method investees	5,626	2,601
Other net investing activities	(61)	(2,223)
Net cash used in investing activities	(7,817,886)	(4,520,267)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits	8,486,734	4,337,096
Net (decrease) increase in short-term borrowings	(21,143)	30,916
FHLB advances:
Proceeds	0	10,200
Repayment	(405,000)	(100,200)
Repurchase agreements:
Proceeds from repurchase agreements	0	48,063
Repayment of repurchase agreements	0	(150,000)
Repurchase agreements’ extinguishment cost	0	(8,740)
Long-term debt and lease liabilities:
Proceeds from long-term debt	0	1,437,269
Repayment of long-term debt and lease liabilities	(909)	(10,609)
Common stock:
Repurchase of common stocks pursuant to the Stock Repurchase Program	0	(145,966)
Proceeds from issuance pursuant to various stock compensation plans and agreements	1,180	1,170
Stocks tendered for payment of withholding taxes	(15,508)	(7,656)
Cash dividends paid	(141,911)	(119,185)
Net cash provided by financing activities	7,903,443	5,322,358
Effect of exchange rate changes on cash and cash equivalents	3,542	11,603
NET INCREASE IN CASH AND CASH EQUIVALENTS	834,930	1,245,792
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	4,017,971	3,261,149
CASH AND CASH EQUIVALENTS, END OF PERIOD	4,852,901	4,506,941
Cash paid during the period for:
Interest	70,833	188,657
Income taxes, net	137,452	82,114
Noncash investing and financing activities:
Loans transferred from held-for-investment to held-for-sale	411,416	253,302
Loans transferred to OREO and other foreclosed assets	$ 49,122	$ 19,504