Employee Benefit Plans - Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 plan
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit pension plans | plan			2
Costs associated with shared plans		$ 0.1
Number of defined contribution retirement plans | plan			3
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Pension obligations assumed	$ 55.6
Plan assets assumed	34.1
Postretirement Health and Other Plans
Defined Benefit Plan Disclosure [Line Items]
Pension obligations assumed	6.8
Net transfer	28.3
After-tax deferred gain on pension obligations	$ 6.1