INVESTMENTS - Share of Equity of Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Equity Method Investments [Line Items]
Income (loss)	$ (3,209)	$ (169)	$ (2,944)	$ (553)
Advanced Engine Repair JV
Schedule of Equity Method Investments [Line Items]
Income (loss)	(594)	(242)	(1,185)	(443)
JGP Energy Partners LLC
Schedule of Equity Method Investments [Line Items]
Income (loss)	0	92	0	(128)
Intermodal Finance I, Ltd.
Schedule of Equity Method Investments [Line Items]
Income (loss)	(33)	(19)	(83)	18
Long Ridge Terminal LLC
Schedule of Equity Method Investments [Line Items]
Income (loss)	$ (2,582)	$ 0	$ (1,676)	$ 0