Represents the weighted average performance risk for derivative contracts as a percentage of unadjusted liabilities.

No definition available.

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- Definition

Represents the performance risk for derivative contracts as a percentage of unadjusted liabilities.

+ References

No definition available.

+ Details

Name:	nty_DerivativePerformanceRiskAsPercentageOfUnadjustedLiabilities
Namespace Prefix:	nty_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

Amount of gain (loss) recognized in earnings, arising from liabilities measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents a liability measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Fair Value of Financial Instruments (Details 2) (Cross currency swaps, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Level 3 activity
Beginning balance:	$ (18,859)	$ (16,337)	$ (11,126)
Realized/unrealized gain (loss) on cross currency swaps	5,009	1,948	(2,724)	(14,389)
Ending balance:	$ (13,850)	$ (14,389)	$ (13,850)	$ (14,389)
Weighted average performance risk for derivative contracts as a percentage of unadjusted liabilities			18.70%
Minimum
Level 3 activity
Performance risk for derivative contracts as a percentage of unadjusted liabilities			16.50%
Maximum
Level 3 activity
Performance risk for derivative contracts as a percentage of unadjusted liabilities			24.40%