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	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net earnings	$ 35,511	$ 47,906	$ 65,117	$ 78,211
Denominator:
Basic shares outstanding	59,807	62,550	59,736	62,825
Dilutive effect of stock options and restricted stock	1,420	2,068	1,347	2,038
Diluted shares outstanding	61,227	64,618	61,083	64,863
Income per common share:
Basic earnings per share	$ 0.59	$ 0.77	$ 1.09	$ 1.24
Diluted earnings per share	$ 0.58	$ 0.74	$ 1.07	$ 1.21