PLEDGED ASSETS - Assets Pledged By Counterparties (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Pledged Assets [Line Items]
Securities Pledged By Counterparties	$ 3,631	$ 4,467
Residential Mortgage Backed Securities [Member] | Pass Through Certificate [Member]
Pledged Assets [Line Items]
Securities Pledged By Counterparties	0	0
USTreasurySecuritiesMember
Pledged Assets [Line Items]
Securities Pledged By Counterparties	0	3,438
Cash
Pledged Assets [Line Items]
Securities Pledged By Counterparties	3,631	1,029
Repurchase Agreement [Member]
Pledged Assets [Line Items]
Securities Pledged By Counterparties	67	4,467
Repurchase Agreement [Member] | Residential Mortgage Backed Securities [Member] | Pass Through Certificate [Member]
Pledged Assets [Line Items]
Securities Pledged By Counterparties	0	0
Repurchase Agreement [Member] | USTreasurySecuritiesMember
Pledged Assets [Line Items]
Securities Pledged By Counterparties	0	3,438
Repurchase Agreement [Member] | Cash
Pledged Assets [Line Items]
Securities Pledged By Counterparties	67	1,029
Derivative [Member]
Pledged Assets [Line Items]
Securities Pledged By Counterparties	3,564	0
Derivative [Member] | Residential Mortgage Backed Securities [Member] | Pass Through Certificate [Member]
Pledged Assets [Line Items]
Securities Pledged By Counterparties	0	0
Derivative [Member] | USTreasurySecuritiesMember
Pledged Assets [Line Items]
Securities Pledged By Counterparties	0	0
Derivative [Member] | Cash
Pledged Assets [Line Items]
Securities Pledged By Counterparties	$ 3,564	$ 0