Revenue (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue	$ 37.4	$ 35.7
Transferred over Time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue	37.4	35.7
Contract assets	$ 56.9	$ 61.7
Revenue from Contract with Customer | Transferred over Time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percentage of concentration	22.00%
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