Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 143,652	$ 101,281
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	13,019	13,960
Provision for loan losses	21,144	30,942
Gain on other real estate owned	(266)	(2,408)
Deferred tax expense	21,361	5,415
Increase in cash surrender value of life insurance contracts	(2,621)	(7,430)
Loss on disposal of other assets	1,501	1,455
Loss on sale of business	1,145
Net decrease in loans held for sale	4,299	8,177
Net amortization of securities premium/discount	16,913	14,944
Amortization of intangible assets	10,940	10,462
Amortization of FDIC indemnification asset		2,427
Stock-based compensation expense	9,821	8,360
Decrease in interest payable and other liabilities	(22,397)	(24,405)
Net payments to FDIC for loss share claims		(935)
Decrease in FDIC loss share receivable		8,613
Decrease in payable to FDIC for loan servicing	(11,113)
Decrease in other assets	13,074	8,259
Other, net	(307)	3,595
Net cash provided by operating activities	220,165	182,712
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale		213,877
Proceeds from maturities of securities available for sale	168,186	157,290
Purchases of securities available for sale	(318,786)	(425,096)
Proceeds from maturities of securities held to maturity	178,625	174,662
Purchases of securities held to maturity	(340,508)	(554,442)
Net (increase) decrease in short-term investments	(11,826)	317,042
Proceeds from sale of loans	32,003	33,279
Net increase in loans	(504,866)	(419,102)
Purchase of life insurance contracts	(1,601)	(50,000)
Purchases of property and equipment	(18,116)	(12,649)
Proceeds from sales of property and equipment	42	16
Proceeds from sales of other real estate	8,010	12,311
Cash received in excess of cash paid for acquisitions		475,659
Proceeds from the sale of business, net of cash sold	77,648
Other, net	(34,241)	(38,414)
Net cash used in investing activities	(765,430)	(115,567)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase (decrease) in deposits	(17,746)	90,040
Net increase (decrease) in short-term borrowings	610,300	(11,134)
Repayments of long-term debt	(39,817)	(121,837)
Net proceeds from issuance of long-term debt	83	83
Dividends paid	(41,775)	(41,594)
Payroll tax remitted on net share settlement of equity awards	(415)	(3,124)
Proceeds from exercise of stock options	1,113	11,427
Proceeds from dividend reinvestment and stock purchase plans	1,646	1,530
Net cash provided by (used in) financing activities	513,389	(74,609)
NET DECREASE IN CASH AND DUE FROM BANKS	(31,876)	(7,464)
CASH AND DUE FROM BANKS, BEGINNING	386,948	372,689
CASH AND DUE FROM BANKS, ENDING	355,072	365,225
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 2,911	$ 2,855