Schedule of Debt [Table Text Block] | | | | | | | | | | | | | | | | | | | | | Borrowings under Credit Facility | | $ | - | | | $ | 12,185 | | | $ | - | | | $ | 3,002 | | Revenue equipment installment notes; weighted average interest rate of 3.3% at December 31, 2016, and 3.6% December 31, 2015, due in monthly installments with final maturities at various dates ranging from January 2017 to December 2022, secured by related revenue equipment | | | 23,986 | | | | 127,840 | | | | 38,461 | | | | 163,387 | | Real estate notes; weighted average interest rate of 2.4% and 2.0% at December 31, 2016 and 2015, respectively, due in monthly installments with fixed maturities at December 2018 and August 2035, secured by related real-estate | | | 1,224 | | | | 28,907 | | | | 1,184 | | | | 30,124 | | | | | (263 | ) | | | (256 | ) | | | (250 | ) | | | (456 | ) | | | | 24,947 | | | | 168,676 | | | | 39,395 | | | | 196,057 | | Principal portion of capital lease obligations, secured by related revenue equipment | | | 2,441 | | | | 19,761 | | | | 4,031 | | | | 10,547 | | | | | | | | | | | | | | | | | | | Total debt and capital lease obligations | | $ | 27,388 | | | $ | 188,437 | | | $ | 43,426 | | | $ | 206,604 | | |
Schedule of Maturities of Long-term Debt [Table Text Block] | | | | | | | $ | 25,210 | | | | | 39,783 | | | | | 29,014 | | | | | 58,424 | | | | | 14,136 | | | | $ | 27,575 | | |