Equity (Schedule of Common Stock Reserved for Future Issuances) (Details) - shares	Dec. 31, 2016	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of outstanding stock options (in shares)	597,972	750,338
Purchases under the employee stock purchase plan (in shares)	1,044,678
Issuance of stock-based awards under the Equity Plans (in shares)	416,358
Purchases under the officer and director share purchase plan (in shares)	88,741
Issuance of deferred stock-based awards under the Directors' Stock Award Plan, as amended (in shares)	28,840
Total reserved (in shares)	3,561,634
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)	1,018,196	878,416
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)	366,849	0