Stockholders' Equity and Earnings per Share - Weighted Average Number of Common Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Equity [Abstract]
Weighted average common shares outstanding - basic (shares)	203,654	209,705	205,017	209,484
Dilutive effect of stock options, restricted stock, and restricted stock units (shares)	1,890	1,456	1,697	1,667
Weighted average common shares outstanding - diluted (shares)	205,544	211,161	206,714	211,151