SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Redeemable Common Stock and Reclassification (Details) - USD ($) $ in Thousands		3 Months Ended		124 Months Ended
	Mar. 20, 2019	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Dec. 31, 2019
Summary of Significant Accounting Policies [Line Items]
Redemptions of common stock	$ 8,600	$ 468	$ 2,539	$ 285,900
Other liabilities		20,419		20,419	$ 19,801
Remaining authorized repurchase amount		400		400
Unfulfilled Redemption Request
Summary of Significant Accounting Policies [Line Items]
Other liabilities		$ 600		$ 600	$ 800
Common Stock
Summary of Significant Accounting Policies [Line Items]
Redemptions of common stock			$ 3
Number of shares non-redeemable due to limitation (in shares)		5,648,158
Number of shares non-redeemable due to limitation		$ 57,000
Common Stock | Share Redemption Program
Summary of Significant Accounting Policies [Line Items]
Redemptions of common stock		$ 500