INCOME TAX EXPENSE (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended					6 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2019	Mar. 31, 2018
Income Tax Expense [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount						$ 2,300
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				35.00%	24.50%	19.00%	69.30%
Effective Income Tax Rate Reconciliation, Percent	12.00%		26.40%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent	4.90%					13.60%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount		$ 2,300
Effective Income Tax Rate Reconciliation, Tax Settlement, Domestic, Percent		8.90%
Effective Income Tax Rate Reconciliation, Tax Settlement, Domestic, Amount	$ 700	$ 2,900				$ 3,600
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	12.10%	114.90%	5.80%			5.80%	3.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		$ 30,300
Effective Income Tax Rate Reconciliation, Tax Credit, Amount						$ 200
Postemployment Benefits Liability			$ 7,500				$ 7,500
Increase in Deferred Tax Liabilities			$ 1,000				1,000
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount							$ 300
Effective Income Tax Rate Reconciliation, Disposition of Business, Percent			1.50%				0.80%
Income Tax Expense (Benefit)	$ 2,558		$ 3,590			$ 8,498	$ (18,280)
Tax Cuts And Jobs Act [Member]
Income Tax Expense [Line Items]
Income Tax Expense (Benefit)			$ 700				$ 24,400