Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 45,412	$ 35,783
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,671	2,857
Net gain on sale of other real estate owned	(249)	(897)
Writedown of other real estate owned	674	823
Provision for loan losses	900	1,700
Deferred tax expense	671	1,122
Net amortization of securities	2,459	2,244
Stock based compensation expense	152	114
Net gain on sale of bank premises and equipment	(1)	43
Net gain on sales and calls of securities	0	0
Decrease in taxes receivable	721	2,748
(Decrease) increase in interest receivable	(111)	257
Increase (decrease) in interest payable	241	(56)
Increase in other assets	(2,760)	(2,214)
(Decrease) increase in accrued expenses and other liabilities	(1,947)	2,957
Total adjustments	3,421	11,698
Net cash provided by operating activities	48,833	47,481
Cash flows from investing activities:
Proceeds from sales and calls of securities available for sale	64,925	109,123
Proceeds from calls and maturities of held to maturity securities	4,089	16,222
Purchases of securities available for sale	(61,207)	(65,977)
Proceeds from maturities of securities available for sale	45,000	0
Purchases of held to maturity securities	0	0
Purchases of Federal Reserve Bank and Federal Home Loan Bank stock	(174)	(144)
Proceeds from redemption of Federal Reserve Bank and Federal Home Loan Bank stock	0	944
Net increase in loans	(192,222)	(152,334)
Net proceeds from sale of building	0	0
Proceeds from dispositions of other real estate owned	2,894	4,593
Proceeds from dispositions of bank premises and equipment	1	0
Purchases of bank premises and equipment	(2,727)	(2,462)
Net cash used in investing activities	(139,421)	(90,035)
Cash flows from financing activities:
Net increase (decrease) in deposits	26,598	(30,801)
Net (decrease) increase in short-term borrowings	(66,614)	7,102
Proceeds from exercise of stock options	1,259	1,858
Stock based award tax withholding payments	(37)	0
Proceeds from sale of treasury stock	1,782	1,878
Purchases of treasury stock	(718)	(1,683)
Dividends paid	(18,973)	(18,877)
Net cash provided by financing activities	(56,703)	(40,523)
Net decrease in cash and cash equivalents	(147,291)	(83,077)
Cash and cash equivalents at beginning of period	612,740	707,274
Cash and cash equivalents at end of period	465,449	624,197
Cash paid during the year for:
Interest paid	13,863	10,884
Income taxes paid	13,778	18,508
Other non cash items:
Transfer of loans to other real estate owned	2,379	3,130
Increase in dividends payable	256	22
Change in unrealized gain on securities available for sale-gross of deferred taxes	(12,908)	5,460
Change in deferred tax effect on unrealized gain (loss) on securities available for sale	3,352	(2,185)
Amortization of net actuarial gain and prior service cost on pension and postretirement plans	(395)	(140)
Change in deferred tax effect of amortization of net actuarial (gain) loss and prior service cost on pension and postretirement plans	$ 103	$ 56