Consolidated Statements of Operations (Unaudited) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Income Statement [Abstract]        
Revenue $ 634,811 $ 470,086 $ 1,211,902 $ 885,838
Costs and expenses:        
Transportation costs 528,022 388,473 1,005,190 729,727
Selling, general and administrative expenses 84,644 70,199 165,162 137,436
Depreciation and amortization 9,033 7,976 17,939 16,014
Income from operations 13,112 3,439 23,612 2,661
Interest expense (3,754) (3,677) (7,504) (7,302)
Income (Loss) before provision for income taxes 9,358 (239) 16,107 (4,640)
Income tax (expense) benefit (1,680) (6) (3,702) 1,523
Net income (loss) $ 7,678 $ (245) $ 12,405 $ (3,117)
Earnings (Loss) per common share:        
Basic (in usd per share) $ 0.28 $ (0.01) $ 0.45 $ (0.11)
Diluted (in usd per share) $ 0.28 $ (0.01) $ 0.45 $ (0.11)