Quarterly report pursuant to Section 13 or 15(d)

Segment Reporting (Details)

v3.10.0.1
Segment Reporting (Details)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2018
USD ($)
Jun. 30, 2017
USD ($)
Jun. 30, 2018
USD ($)
Jun. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Segment Reporting Information [Line Items]          
External revenues $ 330,343 $ 283,876 $ 632,951 $ 545,921  
Depreciation and amortization 10,362 10,219 21,052 20,252  
Share-based compensation expense 2,417 2,064 4,678 4,026  
Interest expense 483 236 854 518  
Operating Income (Loss) 32,870 29,996 57,105 53,738  
Total assets 711,292 664,268 711,292 664,268 $ 692,622
Capital expenditures 11,385 2,010 $ 17,606 4,662  
Number of reportable segments     4    
Expedited LTL [Member]          
Segment Reporting Information [Line Items]          
External revenues 191,159 159,842 $ 359,521 308,021  
Intersegment revenues 1,732 630 3,314 1,216  
Depreciation and amortization 5,557 5,520 11,085 11,084  
Share-based compensation expense 1,877 1,731 3,553 3,377  
Interest expense   1 1 2  
Operating Income (Loss) 26,526 23,047 47,298 41,975  
Total assets 658,125 629,098 658,125 629,098  
Capital expenditures 10,648 1,756 16,705 4,267  
Truckload Expedited [Member]          
Segment Reporting Information [Line Items]          
External revenues 46,903 49,129 90,064 95,368  
Intersegment revenues 2,044 1,322 4,976 2,170  
Depreciation and amortization 1,562 1,590 3,320 3,147  
Share-based compensation expense 166 85 345 180  
Interest expense 2   3    
Operating Income (Loss) 1,717 1,855 1,674 3,610  
Total assets 69,082 57,933 69,082 57,933  
Capital expenditures 36 2 40 8  
Pool Distribution [Member]          
Segment Reporting Information [Line Items]          
External revenues 43,197 37,685 85,804 76,416  
Intersegment revenues 108 71 172 142  
Depreciation and amortization 1,705 1,613 3,509 3,415  
Share-based compensation expense 113 119 229 207  
Operating Income (Loss) 1,589 1,625 2,960 2,991  
Total assets 58,695 51,214 58,695 51,214  
Capital expenditures 576 203 654 286  
Intermodal [Member]          
Segment Reporting Information [Line Items]          
External revenues 49,084 37,220 97,562 66,116  
Intersegment revenues 78 20 169 31  
Depreciation and amortization 1,537 1,496 3,138 2,606  
Share-based compensation expense 210 129 500 262  
Interest expense 24 13 37 24  
Operating Income (Loss) 5,543 3,209 9,012 5,763  
Total assets 151,962 145,343 151,962 145,343  
Capital expenditures 125 49 207 101  
Elimination [Member]          
Segment Reporting Information [Line Items]          
Intersegment revenues (3,962) (2,043) (8,631) (3,559)  
Depreciation and amortization 1        
Share-based compensation expense 51   51    
Interest expense 457 222 813 492  
Operating Income (Loss) (2,505) 260 (3,839) (601)  
Total assets $ (226,572) $ (219,320) $ (226,572) $ (219,320)