Restructuring (Narrative) (Details) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 employee	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) employee
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1.6	$ 5.2		$ 6.1	$ 5.4	$ 7.2
Acquisition-Related Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected number of positions eliminated | employee						170
Restructuring and related cost, number of positions eliminated, period percent						2.00%
Other costs related to repositioning actions	2.6			9.1
Effect on future earnings, amount				23.0
Restructuring and related cost, expected cost remaining	0.3			0.3
2017 Repositioning Program
Restructuring Cost and Reserve [Line Items]
Restructuring charges				2.4
Restructuring and related cost, expected number of positions eliminated | employee			300
Restructuring and related cost, number of positions eliminated, period percent			3.00%
Severance costs				1.1
Other restructuring costs				1.3
Other costs related to repositioning actions						$ 7.5
Effect on future earnings, amount				30.0
Restructuring and related cost, expected cost remaining	$ 3.6			3.6
2017 Repositioning Program | Cumulative
Restructuring Cost and Reserve [Line Items]
Restructuring charges				32.1
Severance costs				31.4
Other restructuring costs				$ 0.7