Acquisitions - Total Consideration Transferred (Details) - USD ($)
12 Months Ended
Jun. 01, 2015
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Business Acquisition [Line Items]        
Contingent consideration, fair value   $ 78,728 $ (5,145) $ 0
Command acquisition, purchase accounting adjustment     $ (1,176,417)  
Command Transportation, LLC        
Business Acquisition [Line Items]        
Cash $ 394,279,778      
Echo common stock, fair value 14,746,000      
Contingent consideration, fair value (1,176,417)      
Command acquisition, purchase accounting adjustment 142,969      
Total consideration transferred $ 407,706,392