Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities
Net income	$ 54,107	$ 41,638
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan losses	16,274	14,946
Depreciation and amortization of premises and equipment	4,644	4,488
Net amortization on securities	2,133	2,430
Amortization of intangible assets	2,010	2,006
Excess tax (benefit) on stock-based compensation	(447)	(1,526)
Stock-based compensation expense	2,954	2,638
Bank owned life insurance income	(2,564)	(2,629)
Trading security purchases	0	(1,293)
Net unrealized losses on trading securities	0	145
Proceeds from sales of loans held for sale	49,572	60,650
Originations and purchases of loans held for sale	(49,243)	(62,163)
Net gains on sales of loans held for sale	(87)	(223)
Net security (gains)	(163)	(2)
Net (gain) on sales and write-down of other real estate owned	(190)	(704)
Impairment write-down of equity security	0	1,312
Net (increase) in other assets	(32,687)	(209)
Net increase in other liabilities	10,862	4,405
Net cash provided by operating activities	57,175	65,909
Investing activities
Net cash used in acquisitions	(7,884)	(4,000)
Securities available for sale:
Proceeds from maturities, calls and principal paydowns	124,873	136,898
Purchases	(98,502)	(162,723)
Securities held to maturity:
Proceeds from maturities, calls and principal paydowns	45,332	52,883
Proceeds from sales	0	764
Purchases	(105,531)	(41,334)
Equity securities:
Proceeds from sales	2,623	0
Other:
Net increase in loans	(288,768)	(186,546)
Proceeds from Federal Home Loan Bank stock redemption	123,642	112,841
Purchases of Federal Reserve and Federal Home Loan Bank stock	(131,159)	(118,848)
Purchases of premises and equipment, net	(2,037)	(2,604)
Proceeds from the sales of other real estate owned	1,282	6,420
Net cash (used in) investing activities	(336,129)	(206,249)
Financing activities
Net increase in deposits	173,813	41,596
Net increase in short-term borrowings	134,874	149,482
Proceeds from issuance of long-term debt	25,000	0
Repayments of long-term debt	(40,091)	(15,129)
Proceeds from the issuance of shares to employee and other stock plans	881	2,007
Cash paid by employer for tax-withholdings on stock issuance	(1,735)	(2,823)
Cash dividends	(20,969)	(20,044)
Net cash provided by financing activities	271,773	155,089
Net (decrease) increase in cash and cash equivalents	(7,181)	14,749
Cash and cash equivalents at beginning of period	159,664	149,181
Cash and cash equivalents at end of period	152,483	163,930
Cash paid during the period for:
Interest expense	15,672	12,404
Income taxes paid, net of refund	22,890	12,886
Noncash investing activities:
Loans transferred to other real estate owned	912	4,882
Acquisitions:
Fair value of assets acquired	$ 6,274	$ 3,096