Consolidated Statements Of Cash Flows - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES:
Net income		$ 213,385	$ 150,691
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses		20,439	21,886
Provision for depreciation and amortization		19,180	19,890
Amortization of investment security premiums, net		11,679	17,827
Investment securities gains (losses), net	[1]	(2,335)	(879)
Net gains on sales of loans held for sale		(2,671)	(3,547)
Origination of loans held for sale		(89,183)	(96,943)
Proceeds from sales and repayments of held for sale		91,671	92,423
Net (increase) decrease in trading securities, excluding unsettled transactions		(23,843)	6,097
Stock-based compensation		6,394	6,195
(Increase) decrease in interest receivable		(1,717)	(428)
Increase (decrease) in interest payable		(601)	(692)
Increase (decrease) in income taxes payable		25,721	1,483
Other changes, net		19,958	(6,939)
Net cash provided by (used in) operating activities		288,077	207,064
INVESTING ACTIVITIES:
Proceeds from sales of investment securities	[1]	192,522	6,552
Proceeds from maturities/pay downs of investment securities	[1]	812,970	910,411
Purchases of investment securities	[1]	(748,707)	(625,931)
Net (increase) decrease in loans		7,978	(234,405)
Proceeds from Securities Purchased under Agreements to Resell		0	100,000
Purchases of land, buildings and equipment		(13,525)	(14,117)
Sales of land, buildings and equipment		1,667	2,527
Net cash provided by (used in) investing activities		252,905	145,037
FINANCING ACTIVITIES:
Net increase (decrease) in non-interest bearing, savings, interest checking and money market deposits		(27,222)	77,562
Net increase (decrease) in time open and C.D.'s		(83,895)	(157,367)
Net increase (decrease) in federal funds purchased and short-term securities sold under agreements to repurchase		(340,379)	(467,461)
Repayment of long-term borrowings		(149)	(146)
Proceeds from Short-term Debt		7,682	0
Purchases of treasury stock		(19,069)	(10,628)
Issuance of stock under equity compensation plans		(9)	(7)
Cash dividends paid on common stock		(50,202)	(45,816)
Cash dividends paid on preferred stock		(4,500)	(4,500)
Net cash provided by (used in) financing activities		(517,743)	(608,363)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect		23,239	(256,262)
Cash, cash equivalents and restricted cash at beginning of year		524,352	801,641
Cash, cash equivalents and restricted cash at June 30		547,591	545,379
Supplemental Cash Flow Information:
Income tax payments, net		24,969	54,621
Interest paid on deposits and borrowings		28,368	21,203
Loans transferred to foreclosed real estate		$ 1,044	$ 461

[1] Available for sale and non-marketable securities