Revenue Revenue (Details textual) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jan. 01, 2018
Revenue from Contract with Customer [Abstract]
Contract assets	$ 10.2	$ 14.5
Contract liabilities	13.8	$ 13.8
Contract liability, revenue recognized	29.8
Remaining performance obligation	$ 68.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-04-01
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Remaining performance obligation, expected timing of satisfaction, percent	86.00%