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Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 3.1			$ 3.1		$ 3.0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	24.50%		35.00%	24.50%	35.00%	35.00%
Weighted Average Deferred Income Tax Provision Rate		25.00%				39.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability		$ 7.5		$ (42.6)
Undistributed Accumulated Foreign Earnings	$ 96.8			$ 96.8

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- Definition

Represents foreign earnings from prior periods that have not been distributed.

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- Definition

The weighted average of the tax rates used to provide deferred tax assets or liabilities for temporary differences based on when the underlying differences are expected to turn.

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- Definition

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

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Amount of income tax expense (benefit) from continuing operations attributable to an adjustment of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

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- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

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