LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Details 3) (USD $)			6 Months Ended			6 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2011 Asset-backed securitization program	Jun. 30, 2011 LC Agreements	Jun. 30, 2011 Surety Bonds	Jun. 30, 2011 Note payable
Financing Arrangements
Maximum borrowing capacity			$ 75,000,000			$ 28,500,000
Debt, floating rate of interest basis			LIBOR, plus a margin
Annual fee on unused portion of the accounts receivable facility (as a percent)			0.575%
Tangible net worth required to be maintained			375,000,000
Number of financial institutions which provide collateralized facilities for the issuance of letters of credit				4
Available borrowing capacity for issuance of letters of credit committed by financial institutions subject to the Company's compliance with the requirements of issuance				39,400,000
Outstanding letters of credit				45,700,000
Outstanding surety bonds					12,700,000
Amounts collateralized by restricted funds	51,681,000	51,661,000		45,200,000	6,500,000
Note payable, term (in months)						36
Note payable to finance revenue equipment purchased						2,000,000
Long-term debt	53,546,000	56,658,000				2,000,000
Long-term debt, less current portion	38,160,000	42,657,000				1,400,000
Current portion of long-term debt	$ 15,386,000	$ 14,001,000				$ 600,000