Retirement Benefit Plan (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Apr. 02, 2011	Mar. 31, 2012	Apr. 02, 2011
Retirement Benefit Plan [Abstract]
Service cost	$ 104	$ 118	$ 211	$ 235
Interest cost	211	195	427	389
Expected return on plan assets	(167)	(173)	(338)	(345)
Net amortization and deferral	20	38	40	75
Net periodic benefit cost	$ 168	$ 178	$ 340	$ 354
Expected rate of return on plan assets (in hundredths)	5.40%			5.20%