Related Party Transactions (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Related Party Transaction [Line Items]
Proceeds from sale leaseback transaction	$ 3,500,000
Dividend payments received		$ 1,300,000	$ 2,500,000	$ 1,800,000
Advisory Agreement
Related Party Transaction [Line Items]
Related party transaction payment			200,000	100,000
Annual advisory fee	100,000		100,000
Payments To Dedicated Carriers Owned By Employees
Related Party Transaction [Line Items]
Related party transaction payment	3,100,000	1,800,000	5,700,000	3,500,000
Facilities Lease
Related Party Transaction [Line Items]
Related party transaction payment	800,000	700,000	1,500,000	1,300,000
Equipment Leases
Related Party Transaction [Line Items]
Related party transaction payment	300,000	$ 200,000	600,000	$ 200,000
Elliott
Related Party Transaction [Line Items]
Daily payment from the closing date until the Refinancing Date			33,333.33
Elliott | Investment Agreement
Related Party Transaction [Line Items]
Payments under agreement	$ 2,000,000		$ 2,000,000