INVESTMENT SECURITIES AVAILABLE FOR SALE - Continuous unrealized loss position (Details)
12 Months Ended
Dec. 31, 2016
USD ($)
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Dec. 31, 2015
USD ($)
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Dec. 31, 2014
USD ($)
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Securities available for sale:      
Less than 12 Months, Fair value $ 169,216,000 $ 96,287,000  
Less than 12 Months, Unrealized loss 1,925,000 1,663,000  
12 Months or more, Fair value 8,714,000 4,988,000  
12 Months or more, Unrealized loss 109,000 260,000  
Total, Fair value 177,930,000 101,275,000  
Total, Unrealized loss $ 2,034,000 $ 1,923,000  
Unrealized loss      
Number of securities, unrealized losses | item 107 54  
Aggregate depreciation 1.13% 1.86%  
U.S. Treasury securities      
Securities available for sale:      
Less than 12 Months, Fair value $ 75,901,000 $ 42,301,000  
Less than 12 Months, Unrealized loss 72,000 182,000  
Total, Fair value 75,901,000 42,301,000  
Total, Unrealized loss 72,000 182,000  
Government sponsored entity debt securities      
Securities available for sale:      
Less than 12 Months, Fair value 4,107,000 4,229,000  
Less than 12 Months, Unrealized loss 22,000 8,000  
Total, Fair value 4,107,000 4,229,000  
Total, Unrealized loss 22,000 8,000  
Agency mortgage-backed securities      
Securities available for sale:      
Less than 12 Months, Fair value 57,882,000 19,404,000  
Less than 12 Months, Unrealized loss 930,000 167,000  
12 Months or more, Fair value 402,000 1,932,000  
12 Months or more, Unrealized loss 2,000 43,000  
Total, Fair value 58,284,000 21,336,000  
Total, Unrealized loss $ 932,000 210,000  
Non-agency mortgage-backed securities      
Other than temporary impairment:      
Number of other than temporary impairment securities | item     1
Other than temporary impairment, recognized as losses     $ 20,000
Covered non-agency mortgage-backed securities      
Securities available for sale:      
Less than 12 Months, Fair value   14,149,000  
Less than 12 Months, Unrealized loss   1,114,000  
12 Months or more, Fair value   1,431,000  
12 Months or more, Unrealized loss   190,000  
Total, Fair value   15,580,000  
Total, Unrealized loss   $ 1,304,000  
Other than temporary impairment:      
Number of other than temporary impairment securities | item 3 3 1
Other than temporary impairment, recognized as losses $ 824,000 $ 461,000 $ 170,000
State and municipal securities      
Securities available for sale:      
Less than 12 Months, Fair value 20,215,000 4,959,000  
Less than 12 Months, Unrealized loss 567,000 20,000  
12 Months or more, Fair value   812,000  
12 Months or more, Unrealized loss   4,000  
Total, Fair value 20,215,000 5,771,000  
Total, Unrealized loss 567,000 24,000  
Corporate securities      
Securities available for sale:      
Less than 12 Months, Fair value 11,111,000 11,245,000  
Less than 12 Months, Unrealized loss 334,000 172,000  
12 Months or more, Fair value 8,312,000 813,000  
12 Months or more, Unrealized loss 107,000 23,000  
Total, Fair value 19,423,000 12,058,000  
Total, Unrealized loss $ 441,000 $ 195,000