FINANCIAL INFORMATION BY INDUSTRY SEGMENT, GEOGRAPHIC AREA AND PRODUCT LINE (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2016 USD ($) Segment	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
FINANCIAL INFORMATION BY INDUSTRY SEGMENT, GEOGRAPHIC AREA AND PRODUCT LINE [Abstract]
Number of segment | Segment									1
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 122,684	$ 108,152	$ 99,244	$ 100,369	$ 100,137	$ 97,168	$ 104,858	$ 111,934	$ 430,449	$ 414,097	$ 424,666
Property, plant and equipment, net	106,496				93,743				106,496	93,743	100,821
United States [Member] | Reportable Geographical Components [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									62,400	55,989	51,036
Property, plant and equipment, net	50,595				43,239				50,595	43,239	44,585
Asia [Member] | Reportable Geographical Components [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									336,312	328,669	347,669
Property, plant and equipment, net	55,893				50,504				55,893	50,504	56,236
Europe [Member] | Reportable Geographical Components [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									31,737	29,439	25,961
Property, plant and equipment, net	$ 8				$ 0				$ 8	$ 0	$ 0