Goodwill and Intangible Assets - Amortization Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense on identifiable intangible assets	$ 4.5	$ 4.2	$ 9.1	$ 8.5
Expected amortization expenses in year one	18.0		18.0
Expected amortization expenses in year two	18.0		18.0
Expected amortization expenses in year three	18.0		18.0
Expected amortization expenses in year four	18.0		18.0
Expected amortization expenses in year five	$ 18.0		18.0
Goodwill increase during period			$ 0.1