LOANS RECEIVABLE, INCLUDING LOANS HELD FOR SALE - Nonaccrual and Past Due Loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Receivable [Line Items]
Current	$ 325,750,000	$ 134,190,000
Total past due	10,031,000	4,342,000
Total	335,781,000	138,532,000
Recorded investment in accruing loans greater than 90 days past due	3,326,000	2,658,000
Nonaccrual loans that are current	0	0
Financing receivable unpaid principal balance threshold for evaluation	100,000
30-89 Days Past Due
Receivable [Line Items]
Total past due	6,705,000	1,684,000
90 Days Past Due
Receivable [Line Items]
Total past due	3,326,000	2,658,000
Commercial real estate loans
Receivable [Line Items]
Current	632,000	568,000
Total past due	0	0
Total	632,000	568,000
Recorded investment in accruing loans greater than 90 days past due	0	0
Nonaccrual loans that are current	0	0
Commercial real estate loans | 30-89 Days Past Due
Receivable [Line Items]
Total past due	0	0
Commercial real estate loans | 90 Days Past Due
Receivable [Line Items]
Total past due	$ 0	0
Commercial and industrial
Receivable [Line Items]
Period after which loans are reported as past due	90 days
Current	$ 140,616,000	81,101,000
Total past due	6,142,000	3,625,000
Total	146,758,000	84,726,000
Recorded investment in accruing loans greater than 90 days past due	2,387,000	2,551,000
Nonaccrual loans that are current	0	0
Commercial and industrial | 30-89 Days Past Due
Receivable [Line Items]
Total past due	3,755,000	1,074,000
Commercial and industrial | 90 Days Past Due
Receivable [Line Items]
Total past due	$ 2,387,000	2,551,000
Consumer loans
Receivable [Line Items]
Period after which loans are reported as past due	90 days
Current	$ 184,502,000	52,521,000
Total past due	3,889,000	717,000
Total	188,391,000	53,238,000
Recorded investment in accruing loans greater than 90 days past due	939,000	107,000
Nonaccrual loans that are current	0	0
Consumer loans | 30-89 Days Past Due
Receivable [Line Items]
Total past due	2,950,000	610,000
Consumer loans | 90 Days Past Due
Receivable [Line Items]
Total past due	$ 939,000	$ 107,000