REVENUES - Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($) segment	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Revenue from Contract with Customer [Abstract]
Number of reportable segments | segment	1	1
Disaggregation of Revenue [Line Items]
Total revenues	$ 19,858	$ 22,841	$ 67,913	$ 69,444
Interchange and card revenue
Disaggregation of Revenue [Line Items]
Total revenues	5,325	6,529	17,283	21,530
Servicing fees from Partner Bank
Disaggregation of Revenue [Line Items]
Total revenues	10,163	11,823	37,650	31,774
Account fees
Disaggregation of Revenue [Line Items]
Total revenues	2,110	2,569	6,872	7,847
University fees
Disaggregation of Revenue [Line Items]
Total revenues	1,357	1,474	4,406	4,129
Other revenue
Disaggregation of Revenue [Line Items]
Total revenues	903	446	1,702	4,164
Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenues	18,676	21,747	64,439	66,233
Revenue recognized at a point in time | Interchange and card revenue
Disaggregation of Revenue [Line Items]
Total revenues	5,325	6,529	17,283	21,530
Revenue recognized at a point in time | Servicing fees from Partner Bank
Disaggregation of Revenue [Line Items]
Total revenues	10,163	11,823	37,650	31,774
Revenue recognized at a point in time | Account fees
Disaggregation of Revenue [Line Items]
Total revenues	2,110	2,569	6,872	7,847
Revenue recognized at a point in time | University fees
Disaggregation of Revenue [Line Items]
Total revenues	175	380	932	918
Revenue recognized at a point in time | Other revenue
Disaggregation of Revenue [Line Items]
Total revenues	903	446	1,702	4,164
Revenue recognized over time
Disaggregation of Revenue [Line Items]
Total revenues	1,182	1,094	3,474	3,211
Revenue recognized over time | University fees
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,182	$ 1,094	$ 3,474	$ 3,211