Earnings per Share (EPS) and Common Stock - Earnings per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share And Common Stock [Abstract]
Net Income (Loss)	$ 61,398	$ 70,476	$ 199,937	$ 206,244
Weighted-average shares outstanding—Basic	118,483	117,073	118,186	117,114
Dilutive effect of restricted stock units	909	895	886	983
Weighted-average shares outstanding—Diluted	119,392	117,968	119,072	118,097
Earnings per share—Basic	$ 0.52	$ 0.6	$ 1.69	$ 1.76
Earnings per share—Diluted	$ 0.51	$ 0.6	$ 1.68	$ 1.75