REVENUE EARNING EQUIPMENT, NET - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Sep. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue Earning Equipment [Line Items]
Revenue earning equipment depreciation expense				$ 1,900,000	$ 1,800,000	$ 1,300,000
Accelerated depreciation				236,000	223,000	39,000
Policy depreciation				255,000	134,000	40,000
Net earnings (loss)				$ (122,250)	$ (24,410)	$ 284,613
Net earnings (in dollars per share)				$ (2.15)	$ (0.45)	$ 5.43
Minimum
Revenue Earning Equipment [Line Items]
Revenue Earning Equipment, Residual Value Life				12 months
Maximum
Revenue Earning Equipment [Line Items]
Revenue Earning Equipment, Residual Value Life				24 months
Salvage Value
Revenue Earning Equipment [Line Items]
Accelerated depreciation			$ 30,000	$ 92,000
Policy depreciation	$ 30,000			202,000
Impact from review of policy depreciation
Revenue Earning Equipment [Line Items]
Accelerated depreciation	193,000	$ 144,000
Policy depreciation	$ 104,000	$ 53,000
Net earnings (loss)				$ 146,000	$ 219,000
Net earnings (in dollars per share)				$ 2.78	$ 4.19