SHAREHOLDERS' EQUITY (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Changes in shareholder's equity
Beginning Balance	$ 1,019,696
Net earnings	11,524	$ 12,818
Ending Balance	1,015,277	976,162
Common Stock
Changes in shareholder's equity
Beginning Balance	307	306
Ending Balance	307	306
Additional Paid-In Capital
Changes in shareholder's equity
Beginning Balance	297,644	293,682
Stock plans	(1,367)	1,053
Ending Balance	296,277	294,735
Retained Earnings
Changes in shareholder's equity
Beginning Balance	830,989	775,829
Net earnings	11,524	12,818
Dividends paid	(2,079)	(2,084)
Ending Balance	840,434	786,563
Accumulated Other Comprehensive Income (Loss)
Changes in shareholder's equity
Beginning Balance	(2,161)	(3,657)
Foreign currency translation	(2,500)	5,349
Ending Balance	(4,661)	1,692
Treasury Stock
Changes in shareholder's equity
Beginning Balance	(107,083)	(107,134)
Issued under stock plans	(9,997)
Ending Balance	$ (117,080)	$ (107,134)