Employee Benefit Plans - Components of Net Periodic Benefit Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.9	$ 0.9
Interest cost	1.0	0.7
German Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.9	0.9
Interest cost	1.0	0.7
Amortization of net actuarial gains	(0.3)
Expected return on plan assets	(0.1)	(0.1)
Net periodic benefit expense	$ 1.5	$ 1.5