ACQUISITIONS ACQUISITIONS - Assets Acquired and Liabilities Assumed Cornell Cookson (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 04, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Goodwill	$ 502,055		$ 319,139
Cornell Cookson [Member]
Business Acquisition [Line Items]
Accounts receivable		$ 30,400
Inventories		12,586
Property, plant and equipment		35,226
Goodwill		81,634
Intangible assets		36,000
Other current and non-current assets		2,541
Total assets acquired		198,387
Accounts payable and accrued liabilities		12,000
Long-term liabilities		680
Total liabilities assumed		12,680
Total		185,707
Receivables Gross		30,818
Allowance For Accounts Receivable		$ 418