Summary of Significant Accounting Policies - Shares Used in Computing Basic and Diluted Earnings Per Share (Details) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Denominator (thousands of shares):
Average common shares outstanding for basic computation	172,945	172,238
Incremental shares issuable for stock options and awards	2,841	2,467
Average common shares outstanding for diluted computation	175,786	174,705