Inventories (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Inventories
Raw materials	$ 180.2		$ 180.2		$ 159.5
Work-in-process	156.0		156.0		169.5
Finished goods	113.3		113.3		109.9
Demonstration units	36.8		36.8		38.5
Inventories	486.3		486.3		477.4
Inventory-in-transit	51.7		51.7		$ 58.6
Write-down of demonstration inventories to net realizable value	$ 4.9	$ 7.6	$ 9.9	$ 15.2