ACQUISITIONS (Details 1)		3 Months Ended		6 Months Ended		103 Months Ended
	May 01, 2017 USD ($) shares	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) item	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Number of open-deck trucking companies acquired | item						10
Allocation of the purchase price paid to the fair values of the net assets
Goodwill		$ 108,413,000		$ 108,413,000		$ 108,413,000	$ 89,035,000
Business Acquisition, Pro Forma Information [Abstract]
Pro forma revenue		207,191,000	$ 201,146,000	396,206,000	$ 387,246,000
Pro forma net income (loss)		(3,896,000)	$ 2,195,000	(11,981,000)	$ 2,582,000
Schilli Transportation Services, Inc
Business Acquisition [Line Items]
Ownership interest (as a percent)	100.00%
Total consideration paid	$ 27,400,000
Cash payments for business consideration	$ 21,000,000
Number of shares transferred | shares	232,885
Equity transferred	$ 2,300,000
Outstanding debt assumed	4,000,000
Allocation of the purchase price paid to the fair values of the net assets
Accounts receivable	8,798,000
Parts inventory	1,681,000
Equipment held for sale	2,396,000
Property and equipment	41,423,000
Goodwill	10,678,000
Other assets	2,305,000
Deferred tax liabilities	(12,287,000)
Accounts payable and other liabilities	(4,890,000)
Intangible assets		0		0		0
Long-term debt	(22,744,000)
Total	27,360,000
Transaction expenses incurred, not deductible for taxes purposes	$ 400,000
Big Freight Systems, Inc.
Business Acquisition [Line Items]
Ownership interest (as a percent)	100.00%
Total consideration paid	$ 16,700,000
Cash payments for business consideration	$ 12,400,000
Number of shares transferred | shares	109,248
Equity transferred	$ 1,100,000
Outstanding debt assumed	3,200,000
EBITDA multiplier	0.4
Allocation of the purchase price paid to the fair values of the net assets
Accounts receivable	4,914,000
Prepaid and other current assets	576,000
Property and equipment	11,492,000
Goodwill	8,280,000
Other long-term assets	121,000
Accounts payable	1,802,000
Deferred tax liabilities	(2,440,000)
Accrued expenses and other liabilities	(2,199,000)
Intangible assets		$ 0		$ 0		$ 0
Long-term debt	(2,293,000)
Total	16,649,000
Transaction expenses incurred, not deductible for taxes purposes	$ 600,000