OTHER COMPREHENSIVE LOSS - Summary of the Tax Effects (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive loss, before tax	$ (761)	$ (2,338)	$ (3,612)
Other Comprehensive Income (Loss), Tax	(267)	(819)	(1,264)
Unrealized gains and losses on securities available-for-sale:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss) before Reclassifications, before Tax	(503)	(3,307)	(2,369)
Other Comprehensive Income (Loss) before Reclassifications, Tax	(176)	(1,158)	(829)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(327)	(2,149)	(1,540)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	347	20	1,243
Reclassification from AOCI, Current Period, Tax	(122)	(7)	(435)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	225	13	808
Gains on derivative instruments:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss) before Reclassifications, before Tax	106	989	0
Other Comprehensive Income (Loss) before Reclassifications, Tax	37	346	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	69	643	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(17)	0	0
Reclassification from AOCI, Current Period, Tax	6	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(11)	0	0
Total other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive loss, before tax	(761)	(2,338)	(3,612)
Other Comprehensive Income (Loss), Tax	(267)	(819)	(1,264)
Other Comprehensive Income (Loss), Net of Tax	$ (494)	$ (1,519)	$ (2,348)