SHAREHOLDERS' EQUITY (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Changes in shareholder's equity
Beginning balance			$ 1,131,142
Net earnings common stockholders	$ 23,219	$ 17,878	38,388	$ 32,605
Ending balance	1,166,410	1,080,795	1,166,410	1,080,795
Common stock
Changes in shareholder's equity
Beginning balance	308	307	308	307
Stock plans		1		1
Ending balance	308	308	308	308
Additional paid-in-capital
Changes in shareholder's equity
Beginning balance	305,283	300,697	304,850	301,553
Stock plans	2,782	3,487	3,215	2,631
Ending balance	308,065	304,184	308,065	304,184
Retained earnings
Changes in shareholder's equity
Beginning balance	1,002,420	917,682	989,315	905,022
Net earnings common stockholders	23,219	17,878	38,388	32,605
Dividends paid	(2,061)	(2,061)	(4,125)	(4,128)
Ending balance	1,023,578	933,499	1,023,578	933,499
Accumulated other comprehensive income (loss)
Changes in shareholder's equity
Beginning balance	(14,555)	(20,251)	(23,969)	(31,764)
Foreign currency translation	(4,745)	2,233	4,669	13,746
Ending balance	(19,300)	(18,018)	(19,300)	(18,018)
Treasury stock
Changes in shareholder's equity
Beginning balance	(139,362)	(132,037)	(139,362)	(126,961)
Share repurchases	(6,879)	(7,141)	(6,879)	(12,217)
Ending balance	$ (146,241)	$ (139,178)	$ (146,241)	$ (139,178)