LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets held under capital leases or securitized by notes payable
TOTAL PROPERTY, PLANT AND EQUIPMENT, GROSS	$ 1,077,307	$ 1,007,589
Less accumulated amortization	614,335	592,171
TOTAL PROPERTY, PLANT AND EQUIPMENT, NET	462,972	415,418
Assets held under capital leases or securitized by notes payable
Assets held under capital leases or securitized by notes payable
TOTAL PROPERTY, PLANT AND EQUIPMENT, GROSS	115,499	95,532
Less accumulated amortization	38,470	26,759
TOTAL PROPERTY, PLANT AND EQUIPMENT, NET	77,029	68,773
Land and structures (terminals) | Assets held under capital leases or securitized by notes payable
Assets held under capital leases or securitized by notes payable
TOTAL PROPERTY, PLANT AND EQUIPMENT, GROSS	1,794	1,794
Revenue equipment | Assets held under capital leases or securitized by notes payable
Assets held under capital leases or securitized by notes payable
TOTAL PROPERTY, PLANT AND EQUIPMENT, GROSS	111,892	91,925
Service, office and other equipment | Assets held under capital leases or securitized by notes payable
Assets held under capital leases or securitized by notes payable
TOTAL PROPERTY, PLANT AND EQUIPMENT, GROSS	$ 1,813	$ 1,813