Employee Benefit Plans Employee Benefit Plans - Various (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Components of net periodic pension expense:
Interest cost	$ 2.2		$ 2.3	$ 2.3
Expected return on plan assets	(2.8)		(2.8)	(3.2)
Amortization of net loss	1.2		1.5	1.4
Total net periodic pension expense	0.6		1.0	0.5
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	55.5		58.3
Interest cost	2.2		2.3	2.3
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(2.3)		(3.9)
Actuarial gains (losses)	1.6		(1.2)
Projected benefit obligation at year end	57.0		55.5	58.3
Change in plan assets:
Fair value of plan assets at beginning of year	41.1		41.0
Actual return	6.7		3.0
Employer contributions	3.0		1.0
Fair value of plan assets at year end	48.5		41.1	$ 41.0
Funded status (Accrued pension liabilities) (1)	(8.5)	[1]	(14.4)
Unrecognized actuarial loss recognized in accumulated other comprehensive loss	13.2		$ 16.7
Defined Benefit Plan, Amortization of Net Gains (Losses)	$ 0.9
Assumptions used to determine benefit obligation at year end:
Discount rate	3.70%		4.00%	4.00%
Assumptions used to determine net periodic benefit cost:
Discount rate	4.00%		4.00%	3.80%
Expected long-term weighted-average rate of return on plan assets	7.00%		7.00%	7.30%
Expected future benefit payments
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	$ 2.6
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	2.8
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	2.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	3.0
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	3.1
In aggregate during five years thereafter	16.6
Multiemployer Plan, Contributions by Employer	0.3		$ 0.3	$ 0.7
Defined contribution expense	9.7		10.0	10.8
Deferred Compensation Arrangement with Individual, Compensation Expense	0.5		0.3	$ 0.3
Equity Funds [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	28.1
Fair value of plan assets at year end	33.0		28.1
Fixed Income Funds [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	11.7
Fair value of plan assets at year end	12.6		11.7
Other Investments [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	1.3
Fair value of plan assets at year end	$ 2.9		$ 1.3
Minimum [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	60.00%
Minimum [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	26.00%
Minimum [Member] | Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	3.00%
Maximum [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	68.00%
Maximum [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	30.00%
Maximum [Member] | Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage	6.00%

[1] (1) Accrued pension liabilities on the December 31, 2017 consolidated balance sheet includes $0.9 related to Hudson, which is not included in the table above.