Equity and Accumulated Other Comprehensive Loss - Accumulated Other Comprehensive Loss Rollforward (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Loss
Beginning balance	$ 893.5	$ 828.6	$ 889.0	$ 805.2
Ending balance	1,198.7	820.1	1,198.7	820.1
Accumulated other comprehensive loss
Accumulated Other Comprehensive Loss
Beginning balance	(34.5)	4.3	(29.9)	(8.1)
Other comprehensive (loss) income	1.3	(21.5)	(3.6)	(9.4)
Amounts reclassified from accumulated other comprehensive loss, net of income taxes	0.3	0.1	0.6	0.4
Net current-period other comprehensive income, net of taxes	1.6	(21.4)	(3.0)	(9.0)
Ending balance	(32.9)	(17.1)	(32.9)	(17.1)
Foreign currency translation adjustments
Accumulated Other Comprehensive Loss
Beginning balance	(22.4)	14.3	(17.5)	2.2
Other comprehensive (loss) income	1.3	(21.5)	(3.6)	(9.4)
Amounts reclassified from accumulated other comprehensive loss, net of income taxes	0.0	0.0	0.0	0.0
Net current-period other comprehensive income, net of taxes	1.3	(21.5)	(3.6)	(9.4)
Ending balance	(21.1)	(7.2)	(21.1)	(7.2)
Pension liability adjustments, net of taxes
Accumulated Other Comprehensive Loss
Beginning balance	(12.1)	(10.0)	(12.4)	(10.3)
Other comprehensive (loss) income	0.0	0.0	0.0	0.0
Amounts reclassified from accumulated other comprehensive loss, net of income taxes	0.3	0.1	0.6	0.4
Net current-period other comprehensive income, net of taxes	0.3	0.1	0.6	0.4
Ending balance	$ (11.8)	$ (9.9)	$ (11.8)	$ (9.9)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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