CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
INTEREST AND DIVIDEND INCOME:
Loans, including related fees	$ 91,100	$ 86,128	$ 84,022
Securities:
Taxable	14,325	14,506	15,815
Tax-exempt	7,391	7,269	7,194
Other	1,379	1,477	1,645
TOTAL INTEREST AND DIVIDEND INCOME	114,195	109,380	108,676
INTEREST EXPENSE:
Deposits	6,011	4,159	3,934
Short-term borrowings	245	134	70
Other borrowings	82	114	165
TOTAL INTEREST EXPENSE	6,338	4,407	4,169
NET INTEREST INCOME	107,857	104,973	104,507
Provision for loan losses	5,295	3,300	4,700
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	102,562	101,673	99,807
NON-INTEREST INCOME:
Trust and financial services	5,001	5,208	5,586
Service charges and fees on deposit accounts	11,895	10,530	10,145
Other service charges and fees	12,499	12,307	11,798
Securities gain (loss), net	59	34	17
Insurance commissions	74	2,346	6,945
Gain on Sale of certain assets and liabilities of Insurance Brokerage Operation	0	12,822	0
Gain on sale of mortgage loans	1,688	1,842	1,998
Other	4,722	1,842	2,690
TOTAL NON-INTEREST INCOME	35,938	46,931	39,179
Labor and Related Expense	51,322	52,730	60,109
NON-INTEREST EXPENSES:
Occupancy expense	6,897	6,865	6,978
Equipment expense	7,186	7,300	6,991
Federal Deposit Insurance	915	1,300	1,769
Other	22,427	22,113	22,551
TOTAL NON-INTEREST EXPENSE	88,747	90,308	98,398
INCOME BEFORE INCOME TAXES	49,753	58,296	40,588
Provision for income taxes	20,622	19,883	10,392
NET INCOME	29,131	38,413	30,196
OTHER COMPREHENSIVE INCOME
Change in unrealized gains/losses on securities, net of reclassifications and taxes	3,335	(10,130)	(1,225)
Change in funded status of post-retirement benefits, net of taxes	(3,875)	5,367	6,353
COMPREHENSIVE INCOME	$ 28,591	$ 33,650	$ 35,324
EARNINGS PER SHARE:
BASIC AND DILUTED (in dollars per share)	$ 2.38	$ 3.12	$ 2.35
Weighted average number of shares outstanding (in shares)	12,225	12,317	12,836