Goodwill and Intangible Assets (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 3.8	$ 3.3
Annual Future Amortization Expense
Anticipated future amortization expense for 2018	11.5
Anticipated future amortization expense for 2019	15.2
Anticipated future amortization expense for 2020	11.8
Anticipated future amortization expense for 2021	11.1
Anticipated future amortization expense for 2022	$ 10.7