Restructuring Expenses - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2,719	$ 3,978	$ 12,391
Number of positions reduced	52	85	177
Reversal of severance cost	253
Employee separation
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,095	3,978	8,165
Reversal of severance cost	253
Facilities charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,624		$ 4,226