Schedule of Actual and Target Asset Allocation for Pension Plans (Detail)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Target
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	100.00%
Target | Equity securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	68.00%
Target | Debt securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	24.00%
Target | Real estate securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	5.00%
Target | Cash, Cash Equivalents and Marketable Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	3.00%
Actual
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	100.00%	100.00%
Actual | Equity securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	68.00%	74.00%
Actual | Debt securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	21.00%	22.00%
Actual | Real estate securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	5.00%	0.00%
Actual | Cash, Cash Equivalents and Marketable Securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Actual and target asset allocation	6.00%	4.00%