Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
OPERATING ACTIVITIES
Net income	$ 269,345	$ 172,792
Adjustments to reconcile net income to cash provided by operating activities:
Provision (credit) for loan and lease losses	28,501	16,912
Deferred tax expense (benefit)	67,270	(13,328)
Net change in current taxes	17,115	(16,906)
Depreciation	67,749	66,400
Net increase (decrease) in accrued interest payable	401	(1,662)
Net (increase) decrease in income earned not collected	(4,471)	(2,899)
Gain on acquisitions	(134,745)	(5,831)
Securities (gains) losses	(4,664)	(17,509)
Loss on termination of FDIC shared-loss agreements	45	3,377
Origination of loans held for sale	(471,862)	(589,313)
Proceeds from sale of loans held for sale	487,017	564,026
Gain on sale of loans held for sale	(11,317)	(10,857)
(Gain) loss on sale of portfolio loans	(1,007)	(3,758)
Net writedowns/losses on other real estate	3,152	5,251
(Gain) loss on sales of premises and equipment	(490)	0
Net accretion of premiums and discounts	(34,535)	(32,924)
Amortization of intangible assets	16,994	16,633
Reduction FDIC receivable for shared-loss agreements	5,799	11,926
Net increase (decrease) in FDIC payable for shared-loss agreements	3,195	(12,474)
Net change in other assets	(9,566)	17,120
Net change in other liabilities	10,178	56,275
Net cash provided by operating activities	304,104	223,251
INVESTING ACTIVITIES
Net change in loans outstanding	(771,593)	(782,771)
Purchases of investment securities available for sale	(1,891,967)	(2,382,141)
Proceeds from maturities of investment securities held to maturity	20	130
Proceeds from maturities of investment securities available for sale	1,436,113	1,213,333
Proceeds from sales of investment securities available for sale	538,317	1,802,155
Net change in overnight investments	(458,027)	(891,059)
Proceeds from sales of portfolio loans	162,486	77,665
Cash (paid to) received from the FDIC for shared-loss agreements	(7,440)	(16,701)
Net payment to the FDIC for termination of shared-loss agreements	(285)	(20,115)
Proceeds from sale of other real estate	31,072	24,406
Proceeds fro sales of premises and equipment	2,920	0
Additions to premises and equipment	(60,090)	(60,982)
Net cash acquired in business acquisitions	300,703	(727)
Net cash (used) provided by investing activities	(717,771)	(1,036,807)
FINANCING ACTIVITIES
Net change in time deposits	(469,540)	(371,164)
Net change in demand and other interest-bearing deposits	538,084	917,382
Net change in short-term borrowings	(59,207)	93,655
Repayment of long-term obligations	(6,819)	(3,889)
Origination of long-term obligations	175,000	150,000
Cash dividends paid	(7,206)	(10,809)
Net cash provided (used) by financing activities	170,312	775,175
Change in cash and due from banks	(243,355)	(38,381)
Cash and due from banks at beginning of period	539,741	534,086
Cash and due from banks at end of period	296,386	495,705
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Transfers of loans to other real estate	26,926	31,517
Dividends declared but not paid	3,603	0
Transfer of Portfolio Loans and Leases to Held-for-sale	$ 161,719	$ 0