Consolidated Statements Of Cash Flows - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
OPERATING ACTIVITIES:
Net income		$ 224,917	$ 204,480
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses		32,590	25,918
Provision for depreciation and amortization		29,521	30,997
Amortization of investment security premiums, net		28,173	23,357
Investment securities gains (losses), net	[1]	2,158	3,704
Net gains on sales of loans held for sale		(6,200)	(4,924)
Origination of loans held for sale		(162,552)	(115,768)
Proceeds from sales and repayments of held for sale		164,588	117,746
Net (increase) decrease in trading securities, excluding unsettled transactions		7,234	77,262
Stock-based compensation		9,149	8,901
(Increase) decrease in interest receivable		(3,757)	(331)
Increase (decrease) in interest payable		(223)	269
Increase (decrease) in income taxes payable		201	1,787
Other changes, net		8,511	(24,602)
Net cash provided by (used in) operating activities		334,310	348,796
INVESTING ACTIVITIES:
Proceeds from sales of investment securities	[1]	369,036	7,946
Proceeds from maturities/pay downs of investment securities	[1]	1,384,993	1,659,778
Purchases of investment securities	[1]	(1,072,782)	(1,080,003)
Net (increase) decrease in loans		(364,765)	(817,886)
Payments for Securities Purchased under Agreements to Resell		(75,000)	0
Repayments of long-term securities purchased under agreements to resell		100,000	150,000
Purchases of land, buildings and equipment		(22,853)	(18,479)
Sales of land, buildings and equipment		2,570	5,831
Net cash provided by (used in) investing activities		321,199	(92,813)
FINANCING ACTIVITIES:
Net increase (decrease) in non-interest bearing, savings, interest checking and money market deposits		(12,490)	280,495
Net increase (decrease) in time open and C.D.'s		(424,462)	14,510
Net increase (decrease) in federal funds purchased and short-term securities sold under agreements to repurchase		(314,921)	(473,661)
Repayment of long-term borrowings		(218)	(3,872)
Additional long-term borrowings		0	1,469
Proceeds from Short-term Debt		722	0
Purchases of treasury stock		(11,320)	(38,476)
Issuance of stock under equity compensation plans		(7)	(3)
Cash dividends paid on common stock		(68,722)	(65,294)
Cash dividends paid on preferred stock		(6,750)	(6,750)
Net cash provided by (used in) financing activities		(838,168)	(291,582)
Increase (decrease) in cash and cash equivalents		(182,659)	(35,599)
Cash and cash equivalents at beginning of year		782,435	502,719
Cash and cash equivalents at end of period		599,776	467,120
Supplemental Cash Flow Information:
Income tax payments, net		87,449	88,531
Interest paid on deposits and borrowings		32,387	24,438
Loans transferred to foreclosed real estate		1,166	1,031
Transfer of loans held for investment to held for sale		$ 0	$ 42,688

[1] Available for sale and non-marketable securities