Employee Benefit Plans - Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	$ 99.3	$ 104.5
Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	28.4	26.0
Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	60.0	65.6
Level 3
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	10.9	12.9	$ 12.5
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	50.1	51.3
Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	26.2	24.4
Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	23.9	26.9
Global return fund
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	15.7	19.3
Global return fund | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	15.7	19.3
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	11.4	13.7
Corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	11.4	13.7
Government bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	9.0	5.7
Government bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	9.0	5.7
Real estate
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	10.9	12.9
Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0.0	0.0
Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	10.9	12.9
Cash and other short-term investments
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	2.2	1.6
Cash and other short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	2.2	1.6
Cash and other short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	$ 0.0	$ 0.0