Long-term Debt (Tables)

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

	June 30, 2019		December 31, 2018
Line of credit, maturing June 2023	$	800	$	—
Term loan agreement, interest rate of 4.7% and 4.8% at June 30, 2019 and December 31, 2018, respectively maturing June 2023		190,000		195,000
Revenue equipment installment notes with finance companies, weighted average interest rate of 4.8% and 5.0% at June 30, 2019 and December 31, 2018, due in monthly installments with final maturities at various dates through February 2026, secured by related revenue equipment with a net book value of $226.0 million and $197.1 million in June 2019 and December 2018		214,336		184,867
Mortgage note payables, interest rates ranging from 6.26% to 6.99% at June 30, 2019 and December 31, 2018 due in monthly installments with final maturities as various dates through September 2031, secured by real estate with a net book value of $20.7 million and $24.1 million at June 2019 and December 2018		18,301		18,861
Other		1,335		6,872
		424,772		405,600
Less:  Debt issuance costs		(1,211)		(1,347)
Less:  Current maturities of long-term debt		(80,593)		(106,383)
	$	342,968	$	297,870