Stock-based Compensation (Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 1,969	$ 2,020	$ 4,021	$ 3,668
Tax effect on stock-based compensation	(412)	(386)	(832)	(688)
Net effect on net income	1,557	1,634	3,189	2,980
SARS
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Net effect on net income	705	465	1,231	622
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	47	54	98	104
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	729	776	1,496	1,425
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 1,193	$ 1,190	$ 2,427	$ 2,139