SECURITIES - Securities Held to Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Amortized cost and estimated fair value of securities held to maturity [Abstract]
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017	$ 3,861	$ 4,875
Unrealized Gains	0	0
Unrealized Losses	4	17
Securities held to maturity	3,857	4,858
Amortized Cost [Abstract]
Within one year	1,866
After one, but within five years	1,995
After five, but within ten years	0
After ten years	0
Total	3,861
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017	3,861	4,875
Fair Value [Abstract]
Within one year	1,863
After one, but within five years	1,994
After five, but within ten years	0
After ten years	0
Total	3,857
Securities held to maturity	3,857	4,858
Obligations of states and political subdivisions
Amortized cost and estimated fair value of securities held to maturity [Abstract]
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017	2,006	3,020
Unrealized Gains	0	0
Unrealized Losses	0	0
Securities held to maturity	2,006	3,020
Amortized Cost [Abstract]
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017	2,006	3,020
Fair Value [Abstract]
Securities held to maturity	2,006	3,020
Time deposits with other financial institutions
Amortized cost and estimated fair value of securities held to maturity [Abstract]
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017	1,855	1,855
Unrealized Gains	0	0
Unrealized Losses	4	17
Securities held to maturity	1,851	1,838
Amortized Cost [Abstract]
Securities held to maturity, estimated fair value of $4,190 at September 30, 2018 and $3,776 at December 31, 2017	1,855	1,855
Fair Value [Abstract]
Securities held to maturity	1,851	$ 1,838
Mortgage-backed securities, residential
Amortized Cost [Abstract]
Without single maturity date	0
SBA loan pools
Amortized Cost [Abstract]
Without single maturity date	$ 0