SHAREHOLDERS' EQUITY (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Changes in shareholder's equity
Beginning Balance			$ 826,222
Net earnings common stockholders	$ 18,687	$ 20,067	123,286	$ 56,181
Ending Balance	943,457	811,807	943,457	811,807
Common Stock
Changes in shareholder's equity
Beginning Balance	306	305	306	305
Stock plans	1	1	1	1
Ending Balance	307	306	307	306
Common Stock Including Additional Paid in Capital
Changes in shareholder's equity
Beginning Balance	294,787	293,612	292,408	291,190
Stock plans	(2,156)	(2,408)	223	14
Ending Balance	292,631	291,204	292,631	291,204
Retained Earnings
Changes in shareholder's equity
Beginning Balance	785,184	643,018	684,741	606,836
Net earnings common stockholders	18,687	20,067	123,286	56,181
Dividends paid	(2,084)	(2,082)	(6,240)	(6,227)
Adoption of accounting standards updates				4,213
Ending Balance	801,787	661,003	801,787	661,003
Accumulated other comprehensive income (loss)
Changes in shareholder's equity
Beginning Balance	(46,936)	(35,280)	(43,974)	(31,528)
Foreign currency translation	2,802	1,840	(160)	(2,013)
Forward exchange contracts		(7)		94
Ending Balance	(44,134)	(33,447)	(44,134)	(33,447)
Treasury Stock
Changes in shareholder's equity
Beginning Balance	(107,134)	(107,259)	(107,259)	(107,394)
Issued under stock plans			125	135
Ending Balance	$ (107,134)	$ (107,259)	$ (107,134)	$ (107,259)

Amount of the cumulative effect on retained earnings net of related income tax effect.

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Amount of paid and unpaid cash dividends declared for classes of stock, for example, but not limited to, common and preferred.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to parent entity.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Value, after forfeiture, of shares granted under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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