BUSINESS COMBINATIONS - Narrative (Details) $ in Thousands		3 Months Ended		6 Months Ended
	Mar. 01, 2019 USD ($) branch_location shares	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)
Business Acquisition [Line Items]
Total adjustments to other assets		$ (31)
Total adjustments to other liabilities		(500)
Acquisition expense		0	$ 0	$ 905	$ 1,104
Mainland
Business Acquisition [Line Items]
Percentage of voting interests acquired	100.00%
Merger consideration, aggregate shares of common stock (in shares) | shares	763,849
Total consideration transferred	$ 18,600
Total assets acquired	128,372
Loans	82,431
Deposits	107,646
Goodwill	$ 4,554
Number of branch locations | branch_location	3
Contractually required principal and interest payments of the loans acquired	$ 91,900
Amount not expected to be collected	$ 1,300
Pro forma tax expense				1,600
Interest income of acquiree		1,500		2,100
Noninterest income of acquiree		79		100
Net income of acquiree		$ 700		$ 1,000