Schedule of Amounts Recognized as Components of Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Pension Plans
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial loss	$ 17,950	$ 43,357
Prior service costs	642	414
Income tax benefits related to above items	(4,931)	(14,562)
Unrecognized benefit plan costs, net of tax	13,661	29,209
SERP
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial loss	2,576	3,568
Prior service costs	982	1,402
Income tax benefits related to above items	(1,602)	(2,142)
Unrecognized benefit plan costs, net of tax	$ 1,956	$ 2,828