ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY - Loans By Class Modified As Troubled Debt Restructuring (Details) $ in Thousands	3 Months Ended				9 Months Ended
	Mar. 31, 2020 USD ($) loan	Sep. 30, 2019	Mar. 31, 2019 USD ($) loan	Sep. 30, 2018	Sep. 30, 2019
Financing Receivable, Modifications
Pre-Modification Outstanding Recorded Investment			$ 35
Post-Modification Outstanding Recorded Investment			$ 35
Extension period for modified repayment terms	0 months		0 months
Modified Repayment Terms
Financing Receivable, Modifications
Number of Loans | loan	1		1
Modified Repayment Terms | Minimum
Financing Receivable, Modifications
Extension period for modified repayment terms		0 months			0 months
All Modifications [Member]
Financing Receivable, Modifications
Number of Loans | loan	1		1
Non-working Capital Loans [Member]
Financing Receivable, Modifications
Pre-Modification Outstanding Recorded Investment			$ 35
Post-Modification Outstanding Recorded Investment			$ 35
Extension period for modified repayment terms			0 months
Non-working Capital Loans [Member] | Modified Repayment Terms
Financing Receivable, Modifications
Number of Loans | loan			1
Non-working Capital Loans [Member] | Modified Repayment Terms | Minimum
Financing Receivable, Modifications
Extension period for modified repayment terms				0 months
Non-working Capital Loans [Member] | All Modifications [Member]
Financing Receivable, Modifications
Number of Loans | loan			1
Commercial and Industrial Loans [Member]
Financing Receivable, Modifications
Pre-Modification Outstanding Recorded Investment	$ 788
Post-Modification Outstanding Recorded Investment	$ 122
Extension period for modified repayment terms	0 months
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | Modified Repayment Terms
Financing Receivable, Modifications
Number of Loans | loan	1
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | Modified Repayment Terms | Minimum
Financing Receivable, Modifications
Extension period for modified repayment terms		0 months
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member] | All Modifications [Member]
Financing Receivable, Modifications
Number of Loans | loan	1
Commercial and Industrial Loans [Member] | Owner Occupied Loans [Member]
Financing Receivable, Modifications
Pre-Modification Outstanding Recorded Investment	$ 788
Post-Modification Outstanding Recorded Investment	$ 122