Employee Benefit Plans - Narratives (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure
Estimated net periodic pension expense to be amortized over the next fiscal year	$ 0.6
Projected benefit obligation	53.6	$ 57.0	$ 55.4
Fair value of plan assets	42.8	48.5	41.1
Accrued pension liability	10.8	8.5
Multiemployer plan, contributions by employer	0.4	0.3	0.3
Defined contribution expense	8.7	8.2	6.0
Compensation expense	0.4	0.5	$ 0.3
Hudson
Defined Benefit Plan Disclosure
Accrued pension liability	0.8	0.9
Hudson
Defined Benefit Plan Disclosure
Projected benefit obligation	2.5	2.8
Fair value of plan assets	$ 1.7	$ 1.9