Senior Notes (Detail) (USD $) In Thousands, unless otherwise specified			0 Months Ended		0 Months Ended		0 Months Ended		0 Months Ended		0 Months Ended		0 Months Ended		0 Months Ended		0 Months Ended
Sep. 30, 2014	Sep. 30, 2013	May 07, 2008 Series A	May 07, 2008 Series A	May 07, 2008 Series B	May 07, 2008 Series B	May 07, 2008 Series C	May 07, 2008 Series C	May 07, 2008 Series D	May 07, 2008 Series D	Jul. 14, 2010 Series E	Jul. 14, 2010 Series E	Jul. 14, 2010 Series F	Jul. 14, 2010 Series F	Jul. 14, 2010 Series G	Jul. 14, 2010 Series G	Jul. 14, 2010 Series H	Jul. 14, 2010 Series H
Debt Instrument [Line Items]
Amount	$ 376,000	$ 447,000		$ 41,000		$ 40,000		$ 63,000		$ 131,000		$ 60,000		$ 72,000		$ 28,000		$ 85,000
Interest Rate				6.37%		6.37%		6.71%		7.18%		4.72%		5.04%		5.42%		5.59%
Maturity Date			May 07, 2013		May 07, 2015		May 07, 2015		May 07, 2018		Jul. 14, 2016		Jul. 14, 2017		Jul. 14, 2019		Jul. 14, 2020

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

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

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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

+ 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

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

+ 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

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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