The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization expense related to intangible assets	$ 18,328	$ 16,338	$ 11,630
Estimated intangible asset amortization for 2021	$ 19,000
Customer Relationships [Member] \| Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	20 years
Customer Relationships [Member] \| Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	15 years
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	17 years
Capitalized Software [Member] \| Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	7 years
Capitalized Software [Member] \| Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	3 years