Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Arthur J.Gallagher Co [Member]
Related Party Transaction [Line Items]
Net amount receivable from related parties	$ 0.2		$ 0.2
Print procurement services	0.3	$ 0.4
Insurance and risk management services	0.0	$ 0.1
Enova Inc. [Member]
Related Party Transaction [Line Items]
Net amount receivable from related parties	0.3		$ 0.1
Print procurement services	$ 1.8