FAIR VALUE MEASUREMENTS - Financial Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Assets
Total assets	$ 100,048	$ 242,698
Level 1
Assets
Total assets	100,048	242,517
Level 2
Assets
Total assets	0	0
Level 3
Assets
Total assets	0	181
Market
Assets
Cash and cash equivalents	50,870	226,512
Restricted cash	49,178	16,005
Market | Level 1
Assets
Cash and cash equivalents	50,870	226,512
Restricted cash	49,178	16,005
Market | Level 2
Assets
Cash and cash equivalents	0	0
Restricted cash	0	0
Market | Level 3
Assets
Cash and cash equivalents	0	0
Restricted cash	$ 0	0
Income
Assets
Derivative assets		181
Income | Level 1
Assets
Derivative assets		0
Income | Level 2
Assets
Derivative assets		0
Income | Level 3
Assets
Derivative assets		$ 181