Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
Net income	$ 193,522	$ 202,281
Adjustments to reconcile net income to cash provided by operating activities:
Provision (credit) for loan and lease losses	16,043	20,555
Deferred tax expense (benefit)	(2,835)	45,628
Net change in current taxes	(16,609)	17,404
Depreciation	47,343	45,420
Net increase (decrease) in accrued interest payable	(2,043)	1,344
Net (increase) decrease in income earned not collected	(1,601)	(290)
Gain on acquisitions	0	(134,745)
Securities (gains) losses, net	0	(3,327)
Marketable equity securities gain (loss), net	(5,411)	0
Gain on extinguishment of debt	(25,814)	0
Loss on termination of FDIC shared-loss agreements	0	45
Origination of loans held for sale	(304,580)	(299,136)
Proceeds from sale of loans held for sale	302,766	309,791
Gain on sale of loans held for sale	(5,610)	(6,279)
(Gain) loss on sale of portfolio loans	0	(164)
Net writedowns/losses on other real estate	2,698	2,160
(Gain) loss on sales of premises and equipment	0	(159)
Net accretion of premiums and discounts	(17,240)	(22,918)
Amortization of intangible assets	11,562	11,045
Reduction FDIC receivable for shared-loss agreements	0	4,821
Net increase (decrease) in FDIC payable for shared-loss agreements	2,145	2,118
Net change in other assets	310,635	(34,340)
Net change in other liabilities	14,998	29,647
Net cash provided by operating activities	519,969	190,901
INVESTING ACTIVITIES
Net change in loans outstanding	(360,764)	(462,385)
Purchases of investment securities available for sale	(920,356)	(1,186,883)
Payments to Acquire Marketable Securities	(2,818)	0
Proceeds from maturities of investment securities held to maturity	78,384	18
Proceeds from maturities of investment securities available for sale	797,739	1,140,459
Proceeds from sales of investment securities available for sale	119,273	517,588
Proceeds from Sale and Maturity of Marketable Securities	8,493	0
Net change in overnight investments	175,009	(908,583)
Proceeds from sales of portfolio loans	0	32,294
Cash (paid to) received from the FDIC for shared-loss agreements	0	(5,197)
Net payment to the FDIC for termination of shared-loss agreements	0	(285)
Proceeds from sale of other real estate	15,769	20,236
Proceeds fro sales of premises and equipment	198	2,305
Additions to premises and equipment	(59,603)	(35,912)
Net cash acquired in business acquisitions	(106,298)	300,703
Net cash (used) provided by investing activities	(254,974)	(585,642)
FINANCING ACTIVITIES
Net change in time deposits	(181,889)	(238,751)
Net change in demand and other interest-bearing deposits	704,909	429,684
Net change in short-term borrowings	(201,303)	61,030
Repayment of long-term obligations	(653,929)	(7,985)
Origination of long-term obligations	0	175,000
Cash dividends paid	(8,408)	(7,206)
Net cash provided (used) by financing activities	(340,620)	411,772
Change in cash and due from banks	(75,625)	17,031
Cash and due from banks at beginning of period	336,150	539,741
Cash and due from banks at end of period	260,525	556,772
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Transfers of loans to other real estate	11,868	21,891
Dividends declared but not paid	4,204	3,603
Transfer of Portfolio Loans and Leases to Held-for-sale	$ 0	$ 84,509