FINANCIAL INFORMATION BY INDUSTRY SEGMENT, GEOGRAPHIC AREA AND PRODUCT LINE, SEGMENT REPORTING INFORMATION BY PRODUCT TYPE (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2015 USD ($) Segment	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)
FINANCIAL INFORMATION BY INDUSTRY SEGMENT, GEOGRAPHIC AREA AND PRODUCT LINE [Abstract]
Number of segments | Segment	1
Revenue from External Customer [Line Items]
Revenue	$ 97,168	$ 108,358	$ 313,960	$ 308,329
Tungsten slurries [Member]
Revenue from External Customer [Line Items]
Revenue	43,533	42,170	132,335	117,098
Dielectric slurries [Member]
Revenue from External Customer [Line Items]
Revenue	22,257	29,651	74,322	88,718
Other Metals slurries [Member]
Revenue from External Customer [Line Items]
Revenue	16,927	19,641	55,155	54,782
Polishing pads [Member]
Revenue from External Customer [Line Items]
Revenue	7,735	8,764	25,338	23,934
Data storage slurries [Member]
Revenue from External Customer [Line Items]
Revenue	2,977	4,225	11,277	13,693
Engineered Surface Finishes [Member]
Revenue from External Customer [Line Items]
Revenue	$ 3,739	$ 3,907	$ 15,533	$ 10,104