FINANCIAL INFORMATION BY INDUSTRY SEGMENT, GEOGRAPHIC AREA AND PRODUCT LINE (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 106,533	$ 102,122
Property, plant and equipment, net	119,390		125,020
Revenue from External Customer [Line Items]
Revenue	106,533	102,122
Tungsten slurry [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	40,706	40,728
Revenue from External Customer [Line Items]
Revenue	40,706	40,728
Dielectric slurry [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	30,358	28,007
Revenue from External Customer [Line Items]
Revenue	30,358	28,007
Copper slurry, including barrier and aluminum [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	17,984	16,040
Revenue from External Customer [Line Items]
Revenue	17,984	16,040
Polishing pads [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	8,464	6,930
Revenue from External Customer [Line Items]
Revenue	8,464	6,930
Data storage slurry [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	5,062	4,977
Revenue from External Customer [Line Items]
Revenue	5,062	4,977
Engineered Surface Finishes [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	3,959	5,440
Revenue from External Customer [Line Items]
Revenue	$ 3,959	$ 5,440