Revenue (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue	$ 35.7	$ 39.5
Transferred over Time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue	35.7	39.5
Contract assets	$ 61.7	$ 66.3
Revenue from Contract with Customer | Transferred over Time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percentage of concentration	18.00%
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment term	30 days
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment term	90 days