Earnings Per Share (Reconciliation of Net Earnings to Net Earnings Per Share Basic and Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Net earnings	$ 232,368	$ 171,698	$ 208,649
Denominator:
Basic shares outstanding	59,908	61,517	63,287
Dilutive effect of stock options and restricted stock units	1,574	1,737	2,268
Diluted shares outstanding	61,482	63,254	65,555
Income per common share:
Basic earnings per share	$ 3.88	$ 2.79	$ 3.30
Diluted earnings per share	$ 3.78	$ 2.71	$ 3.18