Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Jul. 05, 2017
Basic earnings per common share:
Net income - basic	$ 31,016	$ 28,470
Weighted shares outstanding - basic (in shares)	54,827	55,076
Basic earnings per share (in dollars per share)	$ 0.57	$ 0.52
Diluted earnings per common share:
Net income - basic	$ 31,016	$ 28,470
Add: Convertible Notes interest expense, net of tax	2,439	2,659
Net income - diluted	$ 33,455	$ 31,129
Weighted shares outstanding - basic (in shares)	54,827	55,076
Equity-based compensation awards - effect of dilution (in shares)	1,541	1,318
Convertible Notes - effect of dilution (in shares)	26,979	30,418
Weighted shares outstanding - diluted (in shares)	83,347	86,812
Diluted earnings per share (in dollars per share)	$ 0.40	$ 0.36
2.375% Convertible Senior Notes, Due 2025 | Senior Notes
Diluted earnings per common share:
Stated interest rate	2.375%	2.375%
3.750% Convertible Senior Notes, Due 2029 | Senior Notes
Diluted earnings per common share:
Stated interest rate	3.75%	3.75%
2024 Convertible Notes | Senior Notes
Diluted earnings per common share:
Stated interest rate	2.875%	2.875%	2.875%
Restricted stock
Diluted earnings per common share:
Potential common shares excluded from the calculation of diluted earnings per common share above (in shares)	1,437	1,581