INVESTMENT SECURITIES AVAILABLE FOR SALE - Continuous unrealized loss position (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) item
Securities available for sale:
Less than 12 Months, Fair value	$ 149,554,000		$ 169,216,000
Less than 12 Months, Unrealized loss	1,502,000		1,925,000
12 Months or more, Fair value	6,835,000		8,714,000
12 Months or more, Unrealized loss	123,000		109,000
Total, Fair value	156,389,000		177,930,000
Total, Unrealized loss	$ 1,625,000		$ 2,034,000
Unrealized loss
Number of securities, unrealized losses | item			107
Aggregate depreciation	1.03%		1.13%
Other than temporary impairment:
Other than temporary impairment, recognized as losses	$ 0	$ 824,000
U.S. Treasury securities
Securities available for sale:
Less than 12 Months, Fair value	45,906,000		$ 75,901,000
Less than 12 Months, Unrealized loss	67,000		72,000
Total, Fair value	45,906,000		75,901,000
Total, Unrealized loss	67,000		72,000
Government sponsored entity debt securities
Securities available for sale:
Less than 12 Months, Fair value	1,595,000		4,107,000
Less than 12 Months, Unrealized loss	7,000		22,000
Total, Fair value	1,595,000		4,107,000
Total, Unrealized loss	7,000		22,000
Agency mortgage-backed securities
Securities available for sale:
Less than 12 Months, Fair value	80,160,000		57,882,000
Less than 12 Months, Unrealized loss	1,028,000		930,000
12 Months or more, Fair value			402,000
12 Months or more, Unrealized loss			2,000
Total, Fair value	80,160,000		58,284,000
Total, Unrealized loss	1,028,000		932,000
State and municipal securities
Securities available for sale:
Less than 12 Months, Fair value	18,863,000		20,215,000
Less than 12 Months, Unrealized loss	359,000		567,000
Total, Fair value	18,863,000		20,215,000
Total, Unrealized loss	359,000		567,000
Corporate securities
Securities available for sale:
Less than 12 Months, Fair value	3,030,000		11,111,000
Less than 12 Months, Unrealized loss	41,000		334,000
12 Months or more, Fair value	6,835,000		8,312,000
12 Months or more, Unrealized loss	123,000		107,000
Total, Fair value	9,865,000		19,423,000
Total, Unrealized loss	$ 164,000		$ 441,000