Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 227,530	$ 160,183
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,740	20,942
Provision for loan losses	28,016	43,982
Gain on other real estate owned	(313)	(1,865)
Deferred tax expense	20,342	8,072
Increase in cash surrender value of life insurance contracts	(6,714)	(10,855)
Loss on disposal of other assets	1,748	1,662
Loss on sale of business	1,145
Net decrease in loans held for sale	10,942	11,583
Net amortization of securities premium/discount	25,440	24,119
Amortization of intangible assets	16,578	16,532
Amortization of FDIC indemnification asset		2,427
Stock-based compensation expense	14,868	12,370
Decrease in interest payable and other liabilities	(2,662)	(5,038)
Net cash receipts from FDIC for loss share claims		2,300
Decrease in FDIC loss share receivable		8,613
Increase (decrease) in payable to FDIC for loan servicing	(11,113)	180,882
(Increase) decrease in other assets	(15,748)	11,446
Other, net	299	17,723
Net cash provided by operating activities	330,098	505,078
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale		213,877
Proceeds from maturities of securities available for sale	253,755	249,270
Purchases of securities available for sale	(365,529)	(578,690)
Proceeds from maturities of securities held to maturity	272,986	276,073
Purchases of securities held to maturity	(375,770)	(554,442)
Net (increase) decrease in short-term investments	(15,690)	331,746
Proceeds from sales of loans and leases	47,481	44,823
Net increase in loans	(706,989)	(770,051)
Purchase of life insurance contracts	(1,601)	(50,000)
Purchases of property and equipment	(32,583)	(16,086)
Proceeds from sales of property and equipment	52	389
Proceeds from sales of other real estate	10,114	15,357
Cash received in excess of cash paid for acquisitions	141,769	476,801
Proceeds from the sale of business, net of cash sold	77,648
Other, net	(50,987)	(28,976)
Net cash used in investing activities	(745,344)	(389,909)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase (decrease) in deposits	(52,709)	181,084
Net increase (decrease) in short-term borrowings	572,757	(84,890)
Repayments of long-term debt	(90,142)	(198,690)
Net proceeds from issuance of long-term debt	124	124
Dividends paid	(65,287)	(62,400)
Payroll tax remitted on net share settlement of equity awards	(563)	(3,235)
Proceeds from exercise of stock options	1,232	11,610
Proceeds from dividend reinvestment and stock purchase plans	2,495	2,314
Net cash provided by (used in) financing activities	367,907	(154,083)
NET DECREASE IN CASH AND DUE FROM BANKS	(47,339)	(38,914)
CASH AND DUE FROM BANKS, BEGINNING	386,948	372,689
CASH AND DUE FROM BANKS, ENDING	339,609	333,775
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 19,542	$ 4,770