Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 169,736	$ 107,516
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	33,061	28,613
Accretion of discount and amortization of premiums, net	(4,931)	(15,855)
Stock compensation costs	5,151	4,575
Deferred tax expenses	2,295	3,718
Provision for credit losses	7,068	1,440
Net gains on sales of loans	(2,754)	(1,927)
Net gains on sales of available-for-sale investment securities	(2,474)	(3,842)
Net gains on sales of premises and equipment	(72,007)	(189)
Originations and purchases of loans held-for-sale	(4,287)	(1,403)
Proceeds from sales and paydowns/payoffs in loans held-for-sale	4,773	2,229
Net change in accrued interest receivable and other assets	93,501	2,057
Net change in accrued expenses and other liabilities	(37,791)	57,957
Other net operating activities	(6,064)	(1,339)
Total adjustments	15,541	76,034
Net cash provided by operating activities	185,277	183,550
Net (increase) decrease in:
Loans held-for-investment	(1,085,449)	(165,726)
Interest-bearing deposits with banks	75,140	(3,531)
Investments in qualified affordable housing partnerships, tax credit and other investments	(38,354)	(8,390)
Purchases of:
Resale agreements	(200,000)	(1,000,000)
Available-for-sale investment securities	(50,936)	(223,873)
Loans held-for-investment	(147,242)	(239,399)
Premises and equipment	(1,191)	(2,259)
Proceeds from sale of:
Available-for-sale investment securities	302,656	652,753
Loans held-for-investment	276,643	151,832
OREO	3,958	384
Premises and equipment	116,021	0
Paydowns and maturities of resale agreements	400,000	1,000,000
Repayments, maturities and redemptions of available-for-sale investment securities	125,006	158,268
Other net investing activities	11,345	10,467
Net cash (used in) provided by investing activities	(212,403)	330,526
Net increase in:
Customer deposits	646,188	1,116,272
Short-term borrowings	(18,524)	9,962
Payments for:
Repayment of FHLB advances	0	(700,000)
Repayment of long-term debt	(5,000)	(5,000)
Repurchase of vested shares due to employee tax liability	(12,154)	(3,054)
Cash dividends on common stocks	(30,039)	(29,325)
Other net financing activities	0	986
Net cash provided by financing activities	580,471	389,841
Effect of exchange rate changes on cash and cash equivalents	2,795	493
NET INCREASE IN CASH AND CASH EQUIVALENTS	556,140	904,410
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	1,878,503	1,360,887
CASH AND CASH EQUIVALENTS, END OF PERIOD	2,434,643	2,265,297
Cash paid (received) during the period for:
Interest	30,361	24,309
Income tax refunds, net	(230)	(28,509)
Noncash investing and financing activities:
Loans held-for-investment transferred to loans held-for-sale, net	278,024	308,722
Held-to-maturity investment security retained from securitization of loans	0	160,135
Dividends payable	$ 891	$ 250