ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in Accumulated Other Comprehensive Income By Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax
Unrealized Gains and (Losses) on Available- for-Sales Securities, Opening Balance	$ 10,818	$ (8,041)	$ (4,796)	$ 784
Unrealized Gains and (Losses) on Available- for-Sales Securities, Other comprehensive income before reclassification	3,935	(3,616)	19,636	(12,519)
Unrealized Gains and (Losses) on Available- for-Sales Securities, Amounts reclassified from accumulated other comprehensive income (loss)	(6)	0	(94)	6
Unrealized Gains and (Losses) on Available- for-Sales Securities, Net current period other comprehensive income	3,929	(3,616)	19,542	(12,513)
Unrealized Gains and (Losses) on Available- for-Sales Securities, Ending Balance		(11,657)		(11,657)
Defined Benefit Pension Gains (Losses), Opening Balance	(1,318)	(1,669)	(1,395)	(1,454)
Defined Benefit Pension Gains (Losses), Other comprehensive income before reclassification	0	0	0	0
Defined Benefit Pension Gains (Losses), Amounts reclassified from accumulated other comprehensive income (loss)	38	50	(116)	(148)
Net of tax amount	38	50	116	148
Defined Benefit Pension Gains (Losses), Ending Balance		(1,619)		(1,619)
Total, Opening Balance	9,500	(9,710)	(6,191)	(670)
Total, Other comprehensive income (loss) before reclassification	3,935	(3,616)	(19,636)	12,519
Total, Amounts reclassified from accumulated other comprehensive income (loss)	32	50	22	154
Total other comprehensive income (loss), net of tax	3,967	(3,566)	19,658	(12,365)
Total, Ending Balance	$ 13,467	$ (13,276)	$ 13,467	(13,276)
Accounting Standards Update 2018-02
Accumulated Other Comprehensive Income (Loss), Net of Tax
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax				140
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax				(313)
Other Comprehensive Income Loss, Adjustment, Net of Tax				(173)
Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss), Net of Tax
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax				(68)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax				0
Other Comprehensive Income Loss, Adjustment, Net of Tax				$ (68)