ACCUMULATED OTHER COMPREHENSIVE LOSS - Summary of Changes in Accumulated Other Comprehensive Income or Loss by Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Changes in accumulated other comprehensive income or loss by component, net of tax [Roll Forward]
Balances			$ 143,748	$ 137,242
Total other comprehensive income (loss)	$ (303)	$ (270)	3,479	3,137
Balances	154,277	144,812	154,277	144,812
Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive income or loss by component, net of tax [Roll Forward]
Balances	(6,972)	(7,535)	(10,754)	(10,942)
Other comprehensive income before reclassification	(324)	(456)	3,425	3,051
Amounts reclassified from accumulated other comprehensive income	21	186	54	86
Total other comprehensive income (loss)	(303)	(270)	3,479	3,137
Balances	(7,275)	(7,805)	(7,275)	(7,805)
Unrealized Gains and Losses on Securities Available for Sale
Changes in accumulated other comprehensive income or loss by component, net of tax [Roll Forward]
Balances	(615)	3,152	(4,356)	210
Other comprehensive income before reclassification	(324)	(456)	3,425	3,051
Amounts reclassified from accumulated other comprehensive income	0	(47)	(8)	(612)
Total other comprehensive income (loss)	(324)	(503)	3,417	2,439
Balances	(939)	2,649	(939)	2,649
Defined Benefit and Other Benefit Plans
Changes in accumulated other comprehensive income or loss by component, net of tax [Roll Forward]
Balances	(6,357)	(10,687)	(6,398)	(11,152)
Other comprehensive income before reclassification	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	21	233	62	698
Total other comprehensive income (loss)	21	233	62	698
Balances	$ (6,336)	$ (10,454)	$ (6,336)	$ (10,454)