FAIR VALUE MEASUREMENT AND DISCLOSURE (Schedule of Carrying Amounts and Estimated Fair Value for Financial Instrument Assets and Liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financial assets:
Available-for-sale Securities	$ 799,000	$ 789,899
Held-to-maturity securities, at amortized cost	93,062	94,073
Held-to-maturity Securities, Fair Value	91,601	94,913
Mortgage servicing rights	1,851	1,766
Financial liabilities:
Time deposits	562,245	512,483
Short-term Debt, Fair Value	591,376	541,605
Long-term Debt, Fair Value	10,654	10,777
Subordinated debentures	47,805	44,333
Residential Real Estate
Financial assets:
Loans receivable, net of allowance	878,089	853,056
Commercial Real Estate
Financial assets:
Loans receivable, net of allowance	1,136,054	1,115,618
Commercial
Financial assets:
Loans receivable, net of allowance	416,096	401,902
Home Equity
Financial assets:
Loans receivable, net of allowance	313,233	318,230
Consumer
Financial assets:
Loans receivable, net of allowance	18,306	17,335
Readily Available Market Prices (Level 1)
Financial assets:
Held-to-maturity Securities, Fair Value	0	0
Mortgage servicing rights	0	0
Financial liabilities:
Time deposits	0	0
Short-term Debt, Fair Value	0	0
Long-term Debt, Fair Value	0	0
Subordinated debentures	0	0
Readily Available Market Prices (Level 1) \| Residential Real Estate
Financial assets:
Loans receivable, net of allowance	0	0
Readily Available Market Prices (Level 1) \| Commercial Real Estate
Financial assets:
Loans receivable, net of allowance	0	0
Readily Available Market Prices (Level 1) \| Commercial
Financial assets:
Loans receivable, net of allowance	0	0
Readily Available Market Prices (Level 1) \| Home Equity
Financial assets:
Loans receivable, net of allowance	0	0
Readily Available Market Prices (Level 1) \| Consumer
Financial assets:
Loans receivable, net of allowance	0	0
Observable Market Data (Level 2)
Financial assets:
Held-to-maturity Securities, Fair Value	91,601	94,913
Mortgage servicing rights	0	0
Financial liabilities:
Time deposits	562,245	512,483
Short-term Debt, Fair Value	591,376	541,605
Long-term Debt, Fair Value	10,654	10,777
Subordinated debentures	47,805	44,333
Observable Market Data (Level 2) \| Residential Real Estate
Financial assets:
Loans receivable, net of allowance	0	0
Observable Market Data (Level 2) \| Commercial Real Estate
Financial assets:
Loans receivable, net of allowance	0	0
Observable Market Data (Level 2) \| Commercial
Financial assets:
Loans receivable, net of allowance	0	0
Observable Market Data (Level 2) \| Home Equity
Financial assets:
Loans receivable, net of allowance	0	0
Observable Market Data (Level 2) \| Consumer
Financial assets:
Loans receivable, net of allowance	0	0
Company Determined Fair Value (Level 3)
Financial assets:
Held-to-maturity Securities, Fair Value	0	0
Mortgage servicing rights	1,851	1,766
Financial liabilities:
Time deposits	0	0
Short-term Debt, Fair Value	0	0
Long-term Debt, Fair Value	0	0
Subordinated debentures	0	0
Company Determined Fair Value (Level 3) \| Residential Real Estate
Financial assets:
Loans receivable, net of allowance	878,089	853,056
Company Determined Fair Value (Level 3) \| Commercial Real Estate
Financial assets:
Loans receivable, net of allowance	1,136,054	1,115,618
Company Determined Fair Value (Level 3) \| Commercial
Financial assets:
Loans receivable, net of allowance	416,096	401,902
Company Determined Fair Value (Level 3) \| Home Equity
Financial assets:
Loans receivable, net of allowance	313,233	318,230
Company Determined Fair Value (Level 3) \| Consumer
Financial assets:
Loans receivable, net of allowance	18,306	17,335
Carrying Amount
Financial assets:
Held-to-maturity securities, at amortized cost	93,062	94,073
Mortgage servicing rights	909	1,025
Financial liabilities:
Time deposits	569,455	517,032
Short-term Debt, Fair Value	591,648	541,796
Long-term Debt, Fair Value	10,756	10,791
Subordinated debentures	58,989	58,911
Carrying Amount \| Residential Real Estate
Financial assets:
Loans receivable, net of allowance	902,131	853,283
Carrying Amount \| Commercial Real Estate
Financial assets:
Loans receivable, net of allowance	1,179,742	1,152,160
Carrying Amount \| Commercial
Financial assets:
Loans receivable, net of allowance	421,688	413,898
Carrying Amount \| Home Equity
Financial assets:
Loans receivable, net of allowance	321,055	321,011
Carrying Amount \| Consumer
Financial assets:
Loans receivable, net of allowance	$ 19,246	$ 17,916

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of investments in debt securities classified as held-to-maturity.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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