Earnings Per Share - Summary of Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Net income (loss) per common share:
Net income (loss)	$ 16,273	$ 35,818	$ (9,563)	$ 52,525
Net income (loss) attributable to common stockholders — basic	16,273	35,818	(9,563)	52,525
Net income (loss) attributable to common stockholders — diluted	$ 16,273	$ 35,818	$ (9,563)	$ 52,525
Denominator:
Basic	150,713,075	154,661,277	150,812,859	154,551,589
Diluted	151,268,535	156,121,476	150,812,859	156,560,502
Basic	$ 0.11	$ 0.23	$ (0.06)	$ 0.34
Diluted	$ 0.11	$ 0.23	$ (0.06)	$ 0.34