Schedule of Fair Values of Pension Plan Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	$ 65,295	$ 52,249
Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	65	72
Equity securities | Domestic Equity Large Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	15,964	20,188
Equity securities | Domestic Equity Mid Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	3,331	5,590
Equity securities | Domestic Equity Small Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	902	1,768
Equity securities | Equity Securities International
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	7,861	5,939
Equity securities | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	15,478
Equity securities | Other Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	1,324	3,217
Fixed Income Securities | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	6,216	6,146
Fixed Income Securities | Corporate Bond Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	3,999	3,652
Fixed Income Securities | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets		805
Fixed Income Securities | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	1,016	973
Fixed Income Securities | Collateralized Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	303	477
Fixed Income Securities | Foreign Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	1,901	1,366
Fixed Income Securities | Real estate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	3,076
Fixed Income Securities | Cash, Cash Equivalents and Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	3,859	2,056
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	59,034	45,877
Fair Value, Inputs, Level 1 | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	7
Fair Value, Inputs, Level 1 | Equity securities | Domestic Equity Large Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	15,964	20,188
Fair Value, Inputs, Level 1 | Equity securities | Domestic Equity Mid Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	3,331	5,590
Fair Value, Inputs, Level 1 | Equity securities | Domestic Equity Small Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	902	1,768
Fair Value, Inputs, Level 1 | Equity securities | Equity Securities International
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	7,861	5,939
Fair Value, Inputs, Level 1 | Equity securities | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	15,478
Fair Value, Inputs, Level 1 | Equity securities | Other Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	1,324	3,217
Fair Value, Inputs, Level 1 | Fixed Income Securities | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	6,216	6,146
Fair Value, Inputs, Level 1 | Fixed Income Securities | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	1,016	973
Fair Value, Inputs, Level 1 | Fixed Income Securities | Real estate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	3,076
Fair Value, Inputs, Level 1 | Fixed Income Securities | Cash, Cash Equivalents and Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	3,859	2,056
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	6,261	6,372
Fair Value, Inputs, Level 2 | Other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	58	72
Fair Value, Inputs, Level 2 | Fixed Income Securities | Corporate Bond Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	3,999	3,652
Fair Value, Inputs, Level 2 | Fixed Income Securities | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets		805
Fair Value, Inputs, Level 2 | Fixed Income Securities | Collateralized Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	303	477
Fair Value, Inputs, Level 2 | Fixed Income Securities | Foreign Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pension plan assets	$ 1,901	$ 1,366