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		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share And Common Stock [Abstract]
Net income	$ 63,504	$ 89,679	$ 138,539	$ 135,768
Weighted-average shares outstanding—Basic	118,260	117,008	118,037	117,135
Dilutive effect of restricted stock units	781	803	875	1,027
Weighted-average shares outstanding—Diluted	119,041	117,811	118,912	118,162
Earnings per share—Basic	$ 0.54	$ 0.77	$ 1.17	$ 1.16
Earnings per share—Diluted	$ 0.53	$ 0.76	$ 1.17	$ 1.15