Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities
Net income	$ 83,914	$ 64,514
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan losses	22,300	22,835
Depreciation and amortization of premises and equipment	6,957	6,759
Net amortization on securities	3,108	3,628
Amortization of intangible assets	3,064	2,999
Excess tax (benefit) on stock-based compensation	(507)	(1,697)
Stock-based compensation expense	3,457	3,195
Bank owned life insurance income	(3,852)	(3,913)
Trading security purchases	0	(1,470)
Net unrealized losses on trading securities	0	(154)
Proceeds from sales of loans held for sale	73,239	87,095
Originations and purchases of loans held for sale	(76,959)	(87,246)
Net gains on sales of loans held for sale	(181)	(292)
Net security (gains) losses	(575)	2
Net losses (gains) on sales and write-down of other real estate owned	130	(189)
Impairment write-down of equity security	0	1,312
Net change in other assets and other liabilities	(14,313)	(810)
Net cash provided by operating activities	99,782	96,568
Investing activities
Net cash used in acquisitions	(7,884)	(4,000)
Securities available for sale:
Proceeds from maturities, calls and principal paydowns	213,732	205,327
Proceeds from sales	0	9,997
Purchases	(102,004)	(232,850)
Securities held to maturity:
Proceeds from maturities, calls and principal paydowns	73,217	86,055
Proceeds from sales	0	764
Purchases	(249,300)	(53,212)
Equity securities:
Proceeds from sales	3,318	0
Purchases	(2)	0
Other:
Net increase in loans	(323,614)	(293,346)
Proceeds from Federal Home Loan Bank stock redemption	186,869	177,803
Purchases of Federal Reserve and Federal Home Loan Bank stock	(192,584)	(175,840)
Proceeds from settlement of bank owned life insurance	0	800
Purchases of premises and equipment, net	(4,256)	(4,177)
Proceeds from the sales of other real estate owned	2,124	6,767
Net cash (used in) investing activities	(400,384)	(275,912)
Financing activities
Net increase in deposits	270,654	257,548
Net increase in short-term borrowings	92,585	248
Proceeds from issuance of long-term debt	25,000	0
Repayments of long-term debt	(40,117)	(15,174)
Proceeds from the issuance of shares to employee and other stock plans	1,140	3,012
Cash paid by employer for tax-withholdings on stock issuance	(1,792)	(3,582)
Cash dividends	(31,899)	(30,073)
Net cash provided by financing activities	315,571	211,979
Net increase in cash and cash equivalents	14,969	32,635
Cash and cash equivalents at beginning of period	159,664	149,181
Cash and cash equivalents at end of period	174,633	181,816
Cash paid during the period for:
Interest expense	26,002	19,771
Income taxes paid, net of refund	31,077	22,230
Noncash investing activities:
Loans transferred to other real estate owned	996	5,227
Acquisitions:
Fair value of assets acquired	$ 6,274	$ 3,096