COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2018 USD ($)	Dec. 31, 2020 USD ($) officer	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Commitment and Contingencies [Line Items]
Outstanding loan commitments and approvals to fund loans		$ 34,100
Future obligations under leases to fund tenant improvements and in other future construction obligation		7,600
Restricted cash		$ 10,013	$ 12,146	$ 22,512
Pending litigation | City and County of San Francisco Real Property Transfer Tax Case
Commitment and Contingencies [Line Items]
Refund sought for penalties, interest and legal fees paid for real property transfer tax	$ 11,800
Executive officers | Employment agreements
Commitment and Contingencies [Line Items]
Number of officers covered under employment agreement | officer		1
Multiplier to annual base salary paid in event of death		2
Multiplier to annual base salary paid in event of disability		1
Restricted cash for tenant improvement allowance
Commitment and Contingencies [Line Items]
Restricted cash		$ 2,800