INVESTMENT SECURITIES - Summary of Investments (Details)	Sep. 30, 2018 USD ($) security	Mar. 01, 2018 USD ($)	Dec. 31, 2017 USD ($) security
Available for sale:
Amortized cost	$ 33,848,000		$ 38,198,000
Gross unrealized gains	74,000		229,000
Gross unrealized losses	1,342,000		436,000
Fair value	32,580,000		37,991,000
Held to maturity:
Amortized cost	1,099,000		2,268,000
Fair value	1,253,000		2,468,000
Fair value of securities pledged to secure public deposits			32,500,000
Available-for-sale [Abstract]
Less Than 12 Months, Fair Value	17,593,000		2,729,000
12 Months or Greater, Fair value	12,714,000		15,117,000
Total, Fair Value	30,307,000		17,846,000
Less Than 12 Months, Unrealized Losses	550,000		16,000
12 Months or Greater, Unrealized Losses	792,000		420,000
Total, Unrealized Losses	1,342,000		436,000
Line of Credit
Held to maturity:
Line of credit facility, maximum borrowing capacity	40,000,000.0	$ 40,000,000
Corporate debt obligations
Available for sale:
Amortized cost	1,000,000		1,000,000
Gross unrealized gains	21,000		33,000
Gross unrealized losses	0		0
Fair value	1,021,000		1,033,000
Residential mortgage-backed securities
Available for sale:
Amortized cost	32,785,000		37,105,000
Gross unrealized gains	52,000		194,000
Gross unrealized losses	1,342,000		436,000
Fair value	31,495,000		36,863,000
Available-for-sale [Abstract]
Less Than 12 Months, Fair Value	17,593,000		2,729,000
12 Months or Greater, Fair value	12,714,000		15,117,000
Total, Fair Value	30,307,000		17,846,000
Less Than 12 Months, Unrealized Losses	550,000		16,000
12 Months or Greater, Unrealized Losses	792,000		420,000
Total, Unrealized Losses	$ 1,342,000		$ 436,000
Collateralized Debt Obligations [Abstract]
Number of securities issued | security	13		11
Collateralized mortgage obligations
Available for sale:
Amortized cost	$ 63,000		$ 93,000
Gross unrealized gains	1,000		2,000
Gross unrealized losses	0		0
Fair value	64,000		95,000
States and political subdivisions
Held to maturity:
Amortized cost	1,099,000		2,268,000
Gross unrealized gains	154,000		200,000
Gross unrealized losses	0		0
Fair value	$ 1,253,000		$ 2,468,000