INVESTMENT SECURITIES - Summary of Unrealized Losses - Held-to-Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Securities with losses under 12 months, Fair Value	$ 31,802	$ 541
Securities with losses under 12 months, Gross Unrealized Loss	362	1
Securities with losses over 12 months, Fair Value	8,645	17,968
Securities with losses over 12 months, Gross Unrealized Loss	323	497
Total, Fair Value	40,447	18,509
Total, Gross Unrealized Loss	685	498
Obligations of state and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Securities with losses under 12 months, Fair Value	8,054	541
Securities with losses under 12 months, Gross Unrealized Loss	39	1
Securities with losses over 12 months, Fair Value	0	505
Securities with losses over 12 months, Gross Unrealized Loss	0	5
Total, Fair Value	8,054	1,046
Total, Gross Unrealized Loss	39	6
GSE mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Securities with losses under 12 months, Fair Value	19,408	0
Securities with losses under 12 months, Gross Unrealized Loss	311	0
Securities with losses over 12 months, Fair Value	0	7,021
Securities with losses over 12 months, Gross Unrealized Loss	0	131
Total, Fair Value	19,408	7,021
Total, Gross Unrealized Loss	311	131
Collateralized mortgage obligations: residential
Schedule of Held-to-maturity Securities [Line Items]
Securities with losses under 12 months, Fair Value	0	0
Securities with losses under 12 months, Gross Unrealized Loss	0	0
Securities with losses over 12 months, Fair Value	8,645	10,442
Securities with losses over 12 months, Gross Unrealized Loss	323	361
Total, Fair Value	8,645	10,442
Total, Gross Unrealized Loss	323	$ 361
Collateralized mortgage obligations: commercial
Schedule of Held-to-maturity Securities [Line Items]
Securities with losses under 12 months, Fair Value	4,340
Securities with losses under 12 months, Gross Unrealized Loss	12
Securities with losses over 12 months, Gross Unrealized Loss	0
Total, Fair Value	4,340
Total, Gross Unrealized Loss	$ 12