Defined benefit and 401(k) savings plan, Components of Net Periodic Pension Cost (Details) - Pension Benefits [Member] $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Net Periodic Benefit Costs [Abstract]
Service cost	$ 0.3
Interest cost	0.1
Expected return on plan assets	(0.1)
Amortization of loss	0.0
Amortization of prior service cost	0.0
Net periodic benefit cost	$ 0.3