Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					$ 0.6
Cost of Revenue	$ 426.7	$ 435.1	$ 876.9	$ 885.5
Selling, General and Administrative Expense	174.1	169.5	351.6	340.6
Costs and Expenses	638.0	646.0	1,316.8	1,307.8
Operating Income (Loss)	48.8	46.3	97.6	106.6
Other Nonoperating Income (Expense)	$ 1.6	(0.8)	$ 2.9	(2.0)
Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of Revenue		435.9		887.1
Selling, General and Administrative Expense		170.0		341.5
Costs and Expenses		647.3		1,310.3
Operating Income (Loss)		45.0		104.1
Other Nonoperating Income (Expense)		0.5		0.5
Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of Revenue		(0.8)		(1.6)
Selling, General and Administrative Expense		(0.5)		(0.9)
Costs and Expenses		(1.3)		(2.5)
Operating Income (Loss)		1.3		2.5
Other Nonoperating Income (Expense)		$ (1.3)		$ (2.5)