SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Restricted Cash and Investment Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Restricted Cash
Restricted Cash	$ 37,292	$ 22,734	$ 68,546
Restricted cash escrow account
Restricted Cash
Restricted Cash	35,100
Restricted cash, escrow account in connection with sale of ground lease
Restricted Cash
Restricted Cash	300
Restricted cash, escrow account in connection with Mitigation Bank | Mitigation Bank
Restricted Cash
Restricted Cash	600
Restricted cash escrow account in connection with reserves for commercial loans and investments
Restricted Cash
Restricted Cash	$ 1,300