Income Tax Provision (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Current income tax provision:
U.S. federal	$ 418	$ 620	$ 837	$ 954
U.S. state and local	95	119	165	177
Non-U.S	33	22	39	37
Total current tax provision	546	761	1,041	1,168
Deferred income tax provision (benefit):
U.S. federal	(10)	16	(10)	(9)
Non-U.S	0	0	0	0
Total deferred tax provision (benefit)	(10)	16	(10)	(9)
Income tax provision	$ 536	$ 777	$ 1,031	$ 1,159