Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2012
Schedule of Operating Leases [Line Items]
Lease expiration period in years	13 years
Lease term	5 years
Minimum
Schedule of Operating Leases [Line Items]
Lease renewal options in years	1 year
Minimum | Subleased and Assigned Leases
Schedule of Operating Leases [Line Items]
Leases expiration year	2015
Maximum
Schedule of Operating Leases [Line Items]
Lease renewal options in years	3 years
Maximum | Subleased and Assigned Leases
Schedule of Operating Leases [Line Items]
Leases expiration year	2024