Related Party Transactions (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Related Party Transaction [Line Items]
Proceeds from sale leaseback transaction	$ 3,500,000	$ 3,500,000
Advisory Agreement
Related Party Transaction [Line Items]
Related party transaction payment		0	$ 100,000	$ 200,000	$ 100,000
Annual advisory fee	$ 100,000	100,000		100,000
Payments To Dedicated Carriers Owned By Employees
Related Party Transaction [Line Items]
Related party transaction payment		1,800,000	1,400,000	3,500,000	2,800,000
Facilities Lease
Related Party Transaction [Line Items]
Related party transaction payment		700,000	200,000	1,300,000	300,000
Equipment Leases
Related Party Transaction [Line Items]
Related party transaction payment		$ 200,000	$ 0	$ 200,000	$ 100,000