Interest Rate Swap Agreement Amount of Gain (Loss) and Reclassification (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012
Interest Rate Swaps [Line Items]
Interest Expense	$ 587		$ 2,594	$ 2,423		$ 7,824
Gains (Losses) on Effective Cash Flow Hedge
Interest Rate Swaps [Line Items]
Net current period other comprehensive income (loss)	691			351
Interest Rate Swap | Gains (Losses) on Effective Cash Flow Hedge | Reclassification out of Accumulated Other Comprehensive Loss
Interest Rate Swaps [Line Items]
Interest Expense	$ 84	[1]		$ 140	[1]

[1] amounts in parenthesis represent a decrease to income