Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total sales	$ 12,749	$ 13,962
Operating segments
Disaggregation of Revenue [Line Items]
Total sales	12,749	13,962
Telco | Operating segments
Disaggregation of Revenue [Line Items]
Total sales	7,502	7,164
Wireless services sales
Disaggregation of Revenue [Line Items]
Total sales	5,246	6,798
Equipment sales: | Telco | Operating segments
Disaggregation of Revenue [Line Items]
Total sales	7,275	6,783
Telco repair sales
Disaggregation of Revenue [Line Items]
Total sales	6	8
Telco recycle sales
Disaggregation of Revenue [Line Items]
Total sales	$ 222	$ 373