Equity (Schedule of Common Stock Reserved for Future Issuances) (Details) - shares	Dec. 31, 2018	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of outstanding stock options (in shares)	68,661	69,980
Purchases under the employee stock purchase plan (in shares)	740,558
Issuance of stock-based awards under the Equity Plans (in shares)	1,879,160
Purchases under the officer and director share purchase plan (in shares)	88,741
Total reserved (in shares)	4,123,525
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)	811,091	1,011,621
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum payout (percentage)	200.00%
Unvested stock units (in shares)	234,324	397,777
Unvested performance stock units (in shares)	535,314

Common Stock, Stock-based Awards Reserved for Future Issuance

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Employee Stock Purchase Plan (ESPP), Shares Reserved for Future Issuances

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Officer and Director Share Purchase Plan, Shares Reserved for Future Issuances

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Maximum Award Potential

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Maximum Award Potential, Percentage

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- Definition

Aggregate number of common shares reserved for future issuance.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-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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Number of options outstanding, including both vested and non-vested options.

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-Topic 718
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