Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 420,726	$ 320,943
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	123,008	98,561
Accretion of discount and amortization of premiums, net	(19,237)	(37,881)
Stock compensation costs	15,780	13,973
Deferred income tax (benefit) expense	(14,500)	3,730
Provision for credit losses	30,749	17,018
Net gains on sales of loans	(6,660)	(6,965)
Net gains on sales of available-for-sale investment securities	(6,733)	(8,468)
Net gains on sales of premises and equipment	(74,092)	(2,916)
Net gain on sale of business	(3,807)	0
Originations and purchases of loans held-for-sale	(15,069)	(10,901)
Proceeds from sales and paydowns/payoffs in loans held-for-sale	15,792	15,065
Net change in accrued interest receivable and other assets	105,729	(2,591)
Net change in accrued expenses and other liabilities	95,432	19,217
Other net operating activities	(2,135)	(1,181)
Total adjustments	244,257	96,661
Net cash provided by operating activities	664,983	417,604
Net increase in:
Loans held-for-investment	(2,967,873)	(776,277)
Interest-bearing deposits with banks	(74,254)	(13,469)
Investments in qualified affordable housing partnerships, tax credit and other investments, net	(121,590)	(57,742)
Purchases of:
Resale agreements	(550,000)	(1,150,000)
Available-for-sale investment securities	(501,669)	(1,330,724)
Loans held-for-investment	(441,141)	(1,038,083)
Premises and equipment	(11,598)	(10,412)
Proceeds from sale of:
Available-for-sale investment securities	676,776	1,008,256
Loans held-for-investment	448,679	545,256
Other real estate owned (“OREO”)	5,431	3,271
Premises and equipment	116,021	8,163
Business, net of cash transferred	3,633	0
Paydowns and maturities of resale agreements	1,000,000	1,450,000
Repayments, maturities and redemptions of available-for-sale investment securities	323,463	870,965
Other net investing activities	27,914	17,527
Net cash used in investing activities	(2,066,208)	(473,269)
Net increase (decrease) in:
Customer deposits	1,385,625	1,130,022
Short-term borrowings	(36,604)	37,699
Proceeds from:
Issuance of common stock pursuant to various stock compensation plans and agreements	1,008	1,962
Payments for:
Repayment of FHLB advances	0	(700,000)
Repayment of long-term debt	(10,000)	(15,000)
Repurchase of vested shares due to employee tax liability	(12,663)	(3,144)
Cash dividends on common stock	(87,880)	(86,984)
Other net financing activities	0	1,019
Net cash provided by financing activities	1,239,486	365,574
Effect of exchange rate changes on cash and cash equivalents	19,985	(3,964)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(141,754)	305,945
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1,878,503	1,360,887
CASH AND CASH EQUIVALENTS, END OF PERIOD	1,736,749	1,666,832
Cash paid during the period for:
Interest paid	98,409	76,750
Income taxes paid	11,800	20,652
Noncash investing and financing activities:
Loans transferred from held-for-investment to held-for-sale	418,489	720,670
Investment security transferred from held-to-maturity to available-for-sale	115,615	0
Held-to-maturity investment security retained from securitization of loans	0	160,135
Loans transferred to OREO	$ 456	$ 6,086