GOODWILL AND INTANGIBLES - Asset Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Mar. 31, 2016
Goodwill [Roll Forward]
Beginning balance	$ 16,463	$ 16,463	$ 16,463
Additions			0
Ending balance	16,463	16,463	16,463
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount				$ 108,388
Amortizable Intangibles, Accumulated amortization				(41,354)
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	46,136		49,432
Amortization expense	(1,520)	(1,139)	(3,375)
Ending balance	44,616	49,432	46,136
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	62,599	67,034	65,895
Additions			79
Amortization expense	(1,520)	(1,139)	(3,375)
Ending balance	61,079	65,895	62,599
North America
Goodwill [Roll Forward]
Ending balance	2,794
Other Regions
Goodwill [Roll Forward]
Ending balance	$ 13,669
Customer Relationship Intangible
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life in years as of June 30, 2017	11 years 6 months 15 days
Amortizable Intangibles, Gross carrying amount				58,530
Amortizable Intangibles, Accumulated amortization				(18,324)
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	$ 36,866	40,206	39,370
Additions			0
Amortization expense	(835)	(836)	(2,504)
Ending balance	36,031	39,370	36,866
Finite-lived Intangible Assets [Roll Forward]
Amortization expense	$ (835)	(836)	(2,504)
Production and Supply Contract Intangible
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life in years as of June 30, 2017	4 years 26 days
Amortizable Intangibles, Gross carrying amount				14,893
Amortizable Intangibles, Accumulated amortization				(6,611)
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	$ 7,850	8,282	8,172
Additions			0
Amortization expense	(518)	(110)	(322)
Ending balance	7,332	8,172	7,850
Finite-lived Intangible Assets [Roll Forward]
Amortization expense	$ (518)	(110)	(322)
Internally Developed Software Intangible
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining useful life in years as of June 30, 2017	2 years 2 months 5 days
Amortizable Intangibles, Gross carrying amount				18,502
Amortizable Intangibles, Accumulated amortization				$ (16,419)
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	$ 1,420	2,083	1,890
Additions			79
Amortization expense	(167)	(193)	(549)
Ending balance	1,253	1,890	1,420
Finite-lived Intangible Assets [Roll Forward]
Amortization expense	$ (167)	$ (193)	$ (549)