Retirement and Other Postretirement Benefit Plans - Schedule of Net Periodic Pension Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Periodic Pension Expense
Defined benefit retirement plans	$ (1.6)	$ 0.6	$ 1.6
Union sponsored multi-employer pension plan	2.1	1.9	2.1
Retirement savings plans-matching contributions	10.2	9.7	7.9
Retirement savings plans-profit sharing contributions	10.2	9.2	10.6
Net periodic expense	$ 20.9	$ 21.4	$ 22.2