Equity and Stock-based Compensation Stock Option Activity (Details) - Stock Options	6 Months Ended
Mar. 31, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period (in shares) \| shares	1,560,441
Granted (in shares) \| shares	0
Exercised (in shares) \| shares	185,413
Forfeited (in shares) \| shares	(35,239)
Outstanding at end of period (in shares) \| shares	1,339,789
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding at beginning of period (USD per share)	$ 7.95
Granted (USD per share)	0.00
Exercised (USD per share)	7.07
Forfeited (USD per share)	17.79
Outstanding at end of period (USD per share)	$ 7.81
Exercisable at end of period (in shares) \| shares	1,137,748
Exercisable at end of period, weighted average exercise price (USD per share)	$ 8.04
Weighted average fair value of options granted during the period	$ 0.00

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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Gross number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Number of options outstanding, including both vested and non-vested options.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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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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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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