The amount of decrease that relates to an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include (a) making lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and (b) purchasing nonparticipating annuity contracts.

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

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

Employee Benefit Plans Narrative (Detail) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended
Employee Benefit Plans Narrative (Detail) (USD $)	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2012 Helix Plan	Jun. 30, 2013 Nexus Plan	Jun. 30, 2013 Nexus Plan Risk Benefits (disability and death)	Jun. 30, 2013 Nexus Plan Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Pension obligation, cash settlement	$ 0	$ 0	$ 87,000	$ 0	$ 6,400,000
Accelerated amortization of prior pension losses					8,900,000	100,000
Minimum age for employees to be admitted into plan							17 years	24 years
Expected contribution						$ 500,000