INVESTMENT SECURITIES HELD TO MATURITY - Continuous unrealized loss position (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($) item
Unrealized loss
Number of securities, unrealized losses | item	31	47
Aggregate depreciation	1.68%	1.40%
State and municipal securities
Securities held to maturity:
Less than 12 Months, Fair value	$ 7,074	$ 13,991
Less than 12 Months, Unrealized loss	83	140
12 Months or more, Fair value	2,754	2,699
12 Months or more, Unrealized loss	85	97
Total, Fair value	9,828	16,690
Total, Unrealized loss	$ 168	$ 237