Earnings Per Share (Details Textual) (USD $)				3 Months Ended		9 Months Ended						9 Months Ended
Earnings Per Share (Details Textual) (USD $)	Jun. 30, 2012	Sep. 30, 2011	Jun. 30, 2011	Jun. 30, 2012 Stock Options [Member]	Jun. 30, 2011 Stock Options [Member]	Jun. 30, 2012 Stock Options [Member]	Jun. 30, 2011 Stock Options [Member]	Jun. 30, 2012 Stock Options [Member] Maximum [Member]	Jun. 30, 2011 Stock Options [Member] Maximum [Member]	Jun. 30, 2012 Stock Options [Member] Minimum [Member]	Jun. 30, 2011 Stock Options [Member] Minimum [Member]	Jun. 30, 2011 Warrant [Member]
Earnings Per Share (Textual) [Abstract]
Option to purchase common stock price per share	$ 15.31	$ 15.55						$ 21.35	$ 22.91	$ 13.06	$ 11.06
Warrants to acquire shares of common stock at a price	8.65		8.65
Options and warrants to purchase shares of common stock				189,037	286,319	189,037	286,319					121,387

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 07-4

-Paragraph 4

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Diluted Earnings Per Share

-URI http://asc.fasb.org/extlink&oid=6510752

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Contingent Stock Agreement

-URI http://asc.fasb.org/extlink&oid=6508534

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Antidilution

-URI http://asc.fasb.org/extlink&oid=6505113

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 128

-Paragraph 171

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 128

-Paragraph 40

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

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+ Details

FIDELITY BANCORP INC 10-Q