LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Assets Sec) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Arrangements
Total assets securing notes payable or held under finance leases	$ 278,806	$ 273,615
Less accumulated depreciation and amortization	76,962	79,961
Net assets securing notes payable or held under finance leases	201,844	193,654
Revenue equipment
Financing Arrangements
Total assets securing notes payable or held under finance leases	260,019	264,396
Land and structures (service centers)
Financing Arrangements
Total assets securing notes payable or held under finance leases	1,794	1,794
Software
Financing Arrangements
Total assets securing notes payable or held under finance leases	1,508	1,484
Service, office, and other equipment
Financing Arrangements
Total assets securing notes payable or held under finance leases	$ 15,485	$ 5,941