INCOME TAX EXPENSE (Details) - USD ($) $ in Thousands		3 Months Ended					9 Months Ended
	Dec. 22, 2017	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Jun. 30, 2017
INCOME TAX EXPENSE
Effective Income Tax Rate Reconciliation, Percent		18.40%		19.40%			19.20%		(28.10%)
Income Tax Expense (Benefit)		$ 4,825		$ 4,297			$ 13,323		$ (13,983)
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount		100	$ 2,300				2,400
Amended return benefit		$ 100	$ 200				$ 300
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Percent		1.00%					4.10%
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Percent		1.80%		1.90%			0.70%		0.90%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent						35.00%	21.00%	24.50%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount				$ 400	$ 1,000	$ (30,300)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent				1.50%					61.70%
Effective Income Tax Rate Reconciliation, Tax Settlement, Domestic, Amount	$ 4,100	$ 500		$ 700		2,900
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount						$ 2,300
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent		2.10%					8.20%		4.70%
Effective Income Tax Rate Reconciliation, Deduction, Amount		$ 300							$ 300
Effective Income Tax Rate Reconciliation, Deduction, Percent		1.00%		2.90%			0.40%		1.40%	1.60%
Additional Pension Contribution to be Made					$ 7,500
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent				1.40%					0.70%
Tax Cuts And Jobs Act [Member]
INCOME TAX EXPENSE
Income Tax Expense (Benefit)				$ 100					$ 24,300