PREPAID EXPENSES AND OTHER - Prepaid Expenses and Other Current Assets (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Chassis converter pool agreements	$ 9,448,000	$ 17,767,000
Assets held for sale	350,000	1,897,000
Income tax receivables	13,160,000	18,073,000
Insurance premiums & maintenance/subscription agreements	5,183,000	4,384,000
Commodity swap contracts	24,736,000	13,750,000
All other	6,470,000	7,165,000
Prepaid expenses and other current assets	59,347,000	63,036,000
Restricted cash	$ 0	$ 0