Summary of Significant Accounting Policies (Earnings Per Share Basic And Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Accounting Policies [Abstract]
Net Income (Loss)	$ 733,997	$ 376,333	$ 245,540
Weighted average shares outstanding	120,005	119,679	118,341
Dilutive effect of employee stock options, restricted shares and restricted stock units	772	1,063	993
Diluted weighted average shares outstanding	120,777	120,742	119,334
Earnings per share-Basic	$ 6.12	$ 3.14	$ 2.07
Earnings per share-Diluted	$ 6.08	$ 3.12	$ 2.06