Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 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	$ 428.1	$ 479.8	$ 1,305.1	$ 1,365.3
Selling, General and Administrative Expense	175.5	170.5	527.1	511.1
Costs and Expenses	640.2	690.6	1,957.0	1,998.3
Operating Income (Loss)	48.1	50.6	145.8	157.3
Other Nonoperating Income (Expense)	$ (1.6)	(1.2)	$ 1.2	(3.2)
Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of Revenue		480.5		1,367.5
Selling, General and Administrative Expense		171.0		512.7
Costs and Expenses		691.8		2,002.1
Operating Income (Loss)		49.4		153.5
Other Nonoperating Income (Expense)		0.0		0.6
Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of Revenue		(0.7)		(2.2)
Selling, General and Administrative Expense		(0.5)		(1.6)
Costs and Expenses		(1.2)		(3.8)
Operating Income (Loss)		1.2		3.8
Other Nonoperating Income (Expense)		$ (1.2)		$ (3.8)