LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Assets Sec) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Arrangements
Total assets securing notes payable or held under finance leases	$ 293,368	$ 293,799
Less accumulated depreciation and amortization	81,672	71,405
Net assets securing notes payable or held under finance leases	211,696	222,394
Revenue equipment
Financing Arrangements
Total assets securing notes payable or held under finance leases	264,884	265,315
Software
Financing Arrangements
Total assets securing notes payable or held under finance leases	2,140	2,140
Service, office, and other equipment
Financing Arrangements
Total assets securing notes payable or held under finance leases	$ 26,344	$ 26,344