ACCUMULATED OTHER COMPREHENSIVE LOSS - Summary of Changes in Accumulated Other Comprehensive Income or Loss by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 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	1,998	1,604
Balances	148,257	141,046
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in accumulated other comprehensive income or loss by component, net of tax [Roll Forward]
Balances	(10,754)	(10,942)
Other comprehensive income before reclassification	1,977	1,936
Amounts reclassified from accumulated other comprehensive income	21	(332)
Total other comprehensive income	1,998	1,604
Balances	(8,756)	(9,338)
Unrealized Gains and Losses on Securities Available for Sale [Member]
Changes in accumulated other comprehensive income or loss by component, net of tax [Roll Forward]
Balances	(4,356)	210
Other comprehensive income before reclassification	1,977	1,936
Amounts reclassified from accumulated other comprehensive income	0	(565)
Total other comprehensive income	1,977	1,371
Balances	(2,379)	1,581
Defined Benefit and Other Benefit Plans [Member]
Changes in accumulated other comprehensive income or loss by component, net of tax [Roll Forward]
Balances	(6,398)	(11,152)
Other comprehensive income before reclassification	0	0
Amounts reclassified from accumulated other comprehensive income	21	233
Total other comprehensive income	21	233
Balances	$ (6,377)	$ (10,919)