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
	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net earnings	$ 41,570	$ 53,373
Denominator:
Basic shares outstanding	62,812	61,991
Dilutive effect of stock options and restricted stock	2,080	2,682
Diluted shares outstanding	64,892	64,673
Income per common share:
Basic earnings per share	$ 0.66	$ 0.86
Diluted earnings per share	$ 0.64	$ 0.83