Stock-Based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation before income taxes	$ 903	$ 1,038	$ 1,714	$ 2,222
Income tax benefit	(293)	(361)	(550)	(775)
Stock-based compensation after income taxes	610	677	1,164	1,447
Cost of Sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation before income taxes	51	83	105	189
Sales and Marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation before income taxes	227	306	426	649
Research and Development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation before income taxes	147	196	295	388
General and Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation before income taxes	$ 478	$ 453	$ 888	$ 996