DEBT ARRANGEMENTS (Note Payable) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 30, 2013	Sep. 30, 2012
Debt Instrument [Line Items]
Long-term debt	$ 5,254	$ 5,842
Net book value of facility and land	9,230
Asking price	10,800
Mortgage Notes Payable, Maturing May 4, 2013 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 31, 2013
Debt instrument, frequency of periodic payments	monthly
Replacement Note Payable Two [Member]
Debt Instrument [Line Items]
Long-term debt	5,254
Debt instrument, maturity date	Oct. 31, 2014
Debt instrument, interest rate	6.00%
Debt instrument, frequency of periodic payments	monthly
Debt instrument, principal payment	47
Debt instrument, face amount	$ 5,786
Debt instrument, variable interest reference rate	LIBOR
Debt instrument, basis spread on variable rate	4.00%
Debt instrument, minimum interest rate	6.00%
Fixed charge coverage ratio	1.25
Total liabilities to tangible net worth ratio	2.10

Assets For Sale Asking Price

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A ratio that indicates a firm's ability to satisfy fixed financing expenses, such as interest and leases.

+ References

No definition available.

+ Details

Name:	basi_FixedChargeCoverageRatio
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Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Ratio that indicates the amount of net worth that has been invested in tangible fixed assets.

+ References

No definition available.

+ Details

Name:	basi_TotalLiabilitiesToTangibleNetWorthRatio
Namespace Prefix:	basi_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

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-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

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-Topic 210

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-Publisher FASB

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-Topic 942

-SubTopic 470

-Section 50

-Paragraph 3

-Subparagraph (c)

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+ Details

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- Definition

When presenting a range of interest rates, the lowest effective rate for funds borrowed under the debt agreement as of the balance sheet date.

+ References

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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- Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7

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

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-Name Accounting Standards Codification

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-Number 210

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-Article 9

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-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20, 22

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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The net book value of the asset(s) sold in connection with the sale of the property to another party and lease back to the seller.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 40

-Section 55

-Paragraph 51

-URI http://asc.fasb.org/extlink&oid=28365400&loc=d3e51840-112757

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+ Details

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Balance Type:	debit
Period Type:	instant