Inventories (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Inventories
Raw materials	$ 177.9		$ 177.9		$ 159.5
Work-in-process	143.1		143.1		169.5
Finished goods	119.6		119.6		109.9
Demonstration units	37.7		37.7		38.5
Inventories	478.3		478.3		477.4
Inventory-in-transit	55.8		55.8		$ 58.6
Write-down of demonstration inventories to net realizable value	$ 5.1	$ 7.4	$ 15.0	$ 22.6