FAIR VALUE - Quantitative Information (Details) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Corporate Bonds and Notes | Recurring | Discounted cash flow
Information related to Level 3 non-recurring fair value measurement [Abstract]
Assets, fair value disclosure	$ 251	$ 250
Corporate Bonds and Notes | Recurring | Discounted cash flow | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit spread	1.73%	1.73%
Corporate Bonds and Notes | Recurring | Discounted cash flow | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit spread	1.73%	1.73%
Corporate Bonds and Notes | Recurring | Discounted cash flow | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit spread	1.73%	1.73%
Impaired Loans: | Non-recurring
Information related to Level 3 non-recurring fair value measurement [Abstract]
Fair value	$ 3,344	$ 2,850
Other real estate owned: | Non-recurring
Information related to Level 3 non-recurring fair value measurement [Abstract]
Fair value	255	344
Other real estate owned: | Non-recurring | Sales comparison
Information related to Level 3 non-recurring fair value measurement [Abstract]
Fair value	255
Derivative Liabilities | Recurring | Historical trend
Information related to Level 3 non-recurring fair value measurement [Abstract]
Liabilities, fair value disclosure	$ 65	$ 68
Derivative Liabilities | Recurring | Historical trend | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit default rate	4.92%	4.92%
Derivative Liabilities | Recurring | Historical trend | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit default rate	4.92%	4.92%
Derivative Liabilities | Recurring | Historical trend | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Credit default rate	4.92%	4.92%
Commercial mortgages | Impaired Loans: | Non-recurring
Information related to Level 3 non-recurring fair value measurement [Abstract]
Fair value	$ 2,599	$ 2,631
Commercial mortgages | Impaired Loans: | Non-recurring | Sales comparison
Information related to Level 3 non-recurring fair value measurement [Abstract]
Fair value	$ 745
Commercial mortgages | Impaired Loans: | Non-recurring | Sales comparison | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	10.00%
Commercial mortgages | Impaired Loans: | Non-recurring | Sales comparison | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	40.04%
Commercial mortgages | Impaired Loans: | Non-recurring | Sales comparison | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	17.05%
Commercial mortgages | Impaired Loans: | Non-recurring | Income approach | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Capitalization Rate	9.00%	9.00%
Commercial mortgages | Impaired Loans: | Non-recurring | Income approach | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Capitalization Rate	10.00%	10.00%
Commercial mortgages | Impaired Loans: | Non-recurring | Income approach | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Capitalization Rate	9.52%	9.52%
Home equity lines and loans | Impaired Loans: | Non-recurring
Information related to Level 3 non-recurring fair value measurement [Abstract]
Fair value		$ 219
Home equity lines and loans | Impaired Loans: | Non-recurring | Sales comparison | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value		22.98%
Home equity lines and loans | Impaired Loans: | Non-recurring | Sales comparison | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value		22.98%
Home equity lines and loans | Impaired Loans: | Non-recurring | Sales comparison | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value		22.98%
Residential mortgages | Other real estate owned: | Non-recurring | Sales comparison | Minimum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	20.80%	20.80%
Residential mortgages | Other real estate owned: | Non-recurring | Sales comparison | Maximum
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	36.37%	48.17%
Residential mortgages | Other real estate owned: | Non-recurring | Sales comparison | Weighted Average
Information related to Level 3 non-recurring fair value measurement [Abstract]
Discount to appraised value	29.88%	30.50%