SHAREHOLDERS' EQUITY (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Changes in shareholder's equity
Beginning balance			$ 1,048,157
Net earnings common stockholders	$ 17,878	$ 16,583	32,605	$ 28,107
Ending balance	1,080,795	1,021,173	1,080,795	1,021,173
Common stock
Changes in shareholder's equity
Beginning balance	307	307	307	307
Stock plans	1		1
Ending balance	308	307	308	307
Additional paid-in-capital
Changes in shareholder's equity
Beginning balance	300,697	296,277	301,553	297,644
Stock plans	3,487	2,076	2,631	709
Ending balance	304,184	298,353	304,184	298,353
Retained earnings
Changes in shareholder's equity
Beginning balance	917,682	840,434	905,022	830,989
Net earnings common stockholders	17,878	16,583	32,605	28,107
Dividends paid	(2,061)	(2,071)	(4,128)	(4,150)
Ending balance	933,499	854,946	933,499	854,946
Accumulated other comprehensive income (loss)
Changes in shareholder's equity
Beginning balance	(20,251)	(4,661)	(31,764)	(2,161)
Foreign currency translation	2,233	(2,811)	13,746	(5,311)
Ending balance	(18,018)	(7,472)	(18,018)	(7,472)
Treasury stock
Changes in shareholder's equity
Beginning balance	(132,037)	(117,080)	(126,961)	(107,083)
Share repurchases	(7,141)	(7,881)	(12,217)	(17,878)
Ending balance	$ (139,178)	$ (124,961)	$ (139,178)	$ (124,961)