Employee Benefit Plans Components of Net Pension Cost (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
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 144	$ 149	$ 322	$ 300
Interest cost	35	248	80	497
Amortization of losses	1	116	3	231
Expected return on assets	(58)	(235)	(135)	(470)
Net periodic pension cost	122	278	270	558
Settlement loss	0	0	87	0
Total pension cost	$ 122	$ 278	$ 357	$ 558