Equity (Schedule of Common Stock Reserved for Future Issuances) (Details) - shares	Dec. 31, 2015	Sep. 30, 2015
Equity [Abstract]
Exercise of outstanding stock options	652,337	696,459
Unvested restricted stock units	574,799
Purchases under the employee stock purchase plan	971,728
Issuance of stock-based awards under the Equity Plans	609,787
Purchases under the officer and director share purchase plan	88,741
Issuance of deferred stock-based awards under the Directors' Stock Award Plan, as amended	15,152
Grants of stock-based awards under the 2007 Directors' Stock Award Plan, as amended	193,010
Total reserved	3,105,554