Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Sep. 12, 2011
Related Party Transaction [Line Items]
Related party income	$ 2.5	$ 0.5
Advisory Agreement
Related Party Transaction [Line Items]
Annual advisory fee			$ 0.1
Due to related parties		0.2
Payments To Dedicated Carriers Owned By Employees
Related Party Transaction [Line Items]
Related party payment	2.6	1.7
Facilities Lease
Related Party Transaction [Line Items]
Related party payment	$ 0.8	$ 0.6