Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income	$ 35,783	$ 31,803
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,857	3,071
Net gain on sale of other real estate owned	(897)	(281)
Writedown of other real estate owned	823	911
Provision for loan losses	1,700	2,350
Deferred tax expense	1,122	3,899
Net amortization of securities	2,244	3,702
Stock based compensation expense	114	168
Net loss on sale/retirement of bank premises and equipment	43	(480)
Net gain on sales of securities	0	(668)
Decrease in taxes receivable	2,748	2,320
Decrease in interest receivable	257	(610)
Decrease in interest payable	(56)	(5)
Increase in other assets	(2,214)	(4,844)
Increase (decrease) in accrued expenses and other liabilities	2,957	(297)
Total adjustments	11,698	9,236
Net cash provided by operating activities	47,481	41,039
Cash flows from investing activities:
Proceeds from sales and calls of securities available for sale	109,123	205,312
Proceeds from calls and maturities of held to maturity securities	16,222	8,435
Purchases of securities available for sale	(65,977)	(250,554)
Proceeds from maturities of securities available for sale	0	550
Purchases of Federal Reserve Bank and Federal Home Loan Bank stock	(144)	(99)
Proceeds from redemption of Federal Reserve Bank and Federal Home Loan Bank stock	944	0
Net increase in loans	(152,334)	(101,292)
Proceeds from dispositions of other real estate owned	4,593	4,860
Proceeds from dispositions of bank premises and equipment	0	674
Purchases of bank premises and equipment	(2,462)	(1,732)
Net cash (used in) provided by investing activities	(90,035)	(133,846)
Cash flows from financing activities:
Net change in deposits	(30,801)	67,860
Net change in short-term borrowings	7,102	(12,022)
Proceeds from exercise of stock options	1,858	760
Proceeds from sale of treasury stock	1,878	1,958
Purchases of treasury stock	(1,683)	(701)
Dividends paid	(18,877)	(18,776)
Net cash provided by financing activities	(40,523)	39,079
Net decrease in cash and cash equivalents	(83,077)	(53,728)
Cash and cash equivalents at beginning of period	707,274	718,156
Cash and cash equivalents at end of period	624,197	664,428
Cash paid during the year for:
Interest paid	10,884	11,594
Income taxes paid	18,508	16,944
Other non cash items:
Transfer of loans to other real estate owned	3,130	3,803
Increase in dividends payable	22	23
Change in unrealized gain on securities available for sale-gross of deferred taxes	5,460	11,807
Change in deferred tax effect on unrealized gain on securities available for sale	(2,185)	(4,723)
Amortization of net actuarial (gain) loss and prior service cost on pension and postretirement plans	(140)	42
Change in deferred tax effect of amortization of net actuarial (gain) loss and prior service cost on pension and postretirement plans	$ 56	$ (17)