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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share And Common Stock [Abstract]
Net Income (Loss)	$ 68,978	$ 61,398	$ 249,810	$ 199,937
Weighted-average shares outstanding—Basic	119,893	118,483	119,533	118,186
Dilutive effect of restricted stock units	929	909	1,060	886
Weighted-average shares outstanding—Diluted	120,822	119,392	120,593	119,072
Earnings per share—Basic	$ 0.58	$ 0.52	$ 2.09	$ 1.69
Earnings per share—Diluted	$ 0.57	$ 0.51	$ 2.07	$ 1.68