Employee Benefit Plans - Projected Benefit Obligation and Plan Asset Fund Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	$ 57.0	$ 55.4
Interest cost	2.1	2.2	$ 2.3
Benefits paid	(2.4)	(2.2)
Actuarial (losses) gains	(3.1)	1.6
Projected benefit obligation at year end	53.6	57.0	55.4
Change in plan assets:
Fair value of plan assets at beginning of year	48.5	41.1
Actual return	(3.3)	6.6
Employer contributions	0.0	3.0
Benefits paid	(2.4)	(2.2)
Fair value of plan assets at year end	42.8	48.5	$ 41.1
Funded status (Accrued pension liabilities)	(10.8)	(8.5)
Unrecognized actuarial loss recognized in accumulated other comprehensive loss	$ 15.8	$ 13.2