Major Customers and Segment Data (Details 3) (USD $) In Thousands	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Pre-tax earnings table
Operating income	$ 40,033	$ 41,138	$ 48,779
Interest income	115	124	456
Other, net	352	138	88
Total earnings before income taxes	40,500	41,400	49,323
Operating segments [Member]
Pre-tax earnings table
Operating income	40,033	41,138	48,779
Interest income	115	124	456
Other, net	352	138	88
Total earnings before income taxes	$ 40,500	$ 41,400	$ 49,323