Postretirement Benefits - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 30, 2013	Sep. 30, 2012
Compensation and Retirement Disclosure [Abstract]
Net (gain) loss	$ (791)	$ 1,226
Amortization of net loss	(3)	(620)
Curtailment loss	(675)	0
Settlement loss	(87)	(8,937)
Total recognized in other comprehensive income (loss)	(1,556)	(8,331)
Total recognized in net periodic pension cost and other comprehensive income (loss)	$ (887)	$ (7,012)

The total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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