Quarterly report pursuant to Section 13 or 15(d)

Segment Reporting (Details)

v3.10.0.1
Segment Reporting (Details)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Segment Reporting Information [Line Items]          
External revenues $ 331,375 $ 298,289 $ 964,325 $ 844,209  
Depreciation and amortization 10,295 10,326 31,346 30,578  
Share-based compensation expense 2,847 1,939 7,525 5,965  
Interest expense 472 288 1,327 806  
Operating Income (Loss) 29,879 27,176 86,984 80,914  
Total assets 743,141 675,400 743,141 675,400 $ 692,622
Capital expenditures 16,738 8,948 $ 34,344 13,610  
Number of reportable segments     4    
Expedited LTL [Member]          
Segment Reporting Information [Line Items]          
External revenues 186,544 164,702 $ 546,066 472,723  
Intersegment revenues 1,963 697 5,276 1,913  
Depreciation and amortization 5,598 5,438 16,682 16,521  
Share-based compensation expense 1,961 1,604 5,595 4,980  
Interest expense   1 1 2  
Operating Income (Loss) 23,724 23,189 71,023 65,164  
Total assets 672,186 638,704 672,186 638,704  
Capital expenditures 15,253 8,372 31,960 12,640  
Truckload Expedited [Member]          
Segment Reporting Information [Line Items]          
External revenues 47,158 49,385 137,221 144,753  
Intersegment revenues 784 2,076 5,761 4,246  
Depreciation and amortization 1,543 1,546 4,863 4,694  
Share-based compensation expense 178 101 524 281  
Interest expense 2   5    
Operating Income (Loss) 1,673 124 3,348 3,734  
Total assets 70,841 59,657 70,841 59,657  
Capital expenditures 30 7 70 15  
Pool Distribution [Member]          
Segment Reporting Information [Line Items]          
External revenues 47,177 40,125 132,980 116,542  
Intersegment revenues 103 58 276 199  
Depreciation and amortization 1,699 1,652 5,208 5,067  
Share-based compensation expense 114 90 342 297  
Operating Income (Loss) 735 681 3,695 3,672  
Total assets 60,672 53,201 60,672 53,201  
Capital expenditures 1,179 239 1,832 524  
Intermodal [Member]          
Segment Reporting Information [Line Items]          
External revenues 50,496 44,077 148,058 110,191  
Intersegment revenues 49 84 217 116  
Depreciation and amortization 1,455 1,690 4,593 4,296  
Share-based compensation expense 262 144 776 407  
Interest expense 10 12 47 36  
Operating Income (Loss) 7,321 3,785 16,333 9,548  
Total assets 159,428 146,836 159,428 146,836  
Capital expenditures 276 330 482 431  
Elimination [Member]          
Segment Reporting Information [Line Items]          
Intersegment revenues (2,899) (2,915) (11,530) (6,474)  
Share-based compensation expense 332   288    
Interest expense 460 275 1,274 768  
Operating Income (Loss) (3,574) (603) (7,415) (1,204)  
Total assets $ (219,986) $ (222,998) $ (219,986) $ (222,998)