Acquisition of Gordon Trucking, Inc. Potential Earn Out Schedule (Details) (USD $)	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 11, 2013
Acquisition of Gordon Trucking [Abstract]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	$ 8,000,000	$ 6,000,000	$ 6,000,000	$ 20,000,000	$ 20,000,000
Earn Out Agreement			13,600,000	13,600,000
Business Combination, Contingent Consideration, Liability, Current			2,300,000
business combination contingent consideration fair value non-current			$ 11,300,000	$ 13,600,000