Leases Adoption of ASC 842 (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total lease liabilities	$ 76.6
Operating lease right-of-use assets	$ 74.5		$ 0.0
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total lease liabilities		$ 73.1
Operating lease right-of-use assets		$ 71.0
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating leases, term of contracts	12 months
Operating leases, option to extend	5 years