COMPREHENSIVE INCOME - Components of AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (AOCI)
Beginning balance	$ 114,712	$ 109,438	$ 94,022
Other comprehensive loss before reclassification	(837)	(367)
Amounts reclassified from AOCI	(507)	76
Net current period OCI	(1,344)	(291)	319
Ending balance	145,625	114,712	109,438
Unrealized gains (losses) on available for-sale securities
Accumulated Other Comprehensive Income (AOCI)
Beginning balance	(363)	(406)
Other comprehensive loss before reclassification	(586)	121
Amounts reclassified from AOCI	(649)	(78)
Net current period OCI	(1,235)	43
Ending balance	(1,598)	(363)	(406)
Defined benefit pension plan items
Accumulated Other Comprehensive Income (AOCI)
Beginning balance	(2,570)	(2,236)
Other comprehensive loss before reclassification	(251)	(488)
Amounts reclassified from AOCI	142	154
Net current period OCI	(109)	(334)
Ending balance	(2,679)	(2,570)	(2,236)
AOCI attributable to parent
Accumulated Other Comprehensive Income (AOCI)
Beginning balance	(2,933)	(2,642)	(2,961)
Net current period OCI	(1,344)	(291)	319
Ending balance	$ (4,277)	$ (2,933)	$ (2,642)