Recently Issued Accounting Standards (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Defined Benefit Plan, Cost Reclassified, Cost of Services			$ 2.0
Defined Benefit Plan, Cost Reclassified, SG&A costs			$ 1.0
Reclassification adjustment to accumulated deficit for stranded other comprehensive taxes arising from tax reform				$ 0.0
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification adjustment to accumulated deficit for stranded other comprehensive taxes arising from tax reform	[1]			32.2
Assets (Fulfillment and Acquisition Costs) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ 30.0
Sales Revenue, Net [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification				(170.0)	$ (170.0)
Cost of Sales [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification				(224.0)	(224.0)
Expense (Fulfillment and Acquisition Costs) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification				$ 1.0	$ 1.0

[1] Per ASU 2018-02, entities can elect to make a one-time reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from newly enacted corporate tax rates under the Tax Cuts and Jobs Act. The Company recorded a provisional amount in 2017.