New Accounting Pronouncements - Additional Information (Details) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating lease, right of use assets	$ 104.7	$ 107.0	$ 55.0
Operating lease, liability	113.7	109.0	57.0
Deferred rent			2.0
Property, Plant and Equipment, Net	558.8	563.0	598.2
Deferred Income Taxes	580.5	580.8	576.4
Retained earnings	$ 3,965.4	3,845.6	3,832.6
Cease-use liability			7.0
ASU 840
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating lease, right of use assets			52.0
Property, Plant and Equipment, Net		(35.2)	35.0
Deferred Income Taxes		4.4	4.0
Retained earnings		$ 13.0	$ 13.0