| Intangible Assets (Details) - USD ($) $ in Thousands | Mar. 31, 2021 | Sep. 30, 2020 | 
|---|---|---|
| Cost | $ 41,730 | $ 41,730 | 
| Accumulated Amortization | 24,946 | 22,887 | 
| Net Book Value | 16,784 | 18,843 | 
| Customer Relationships [Member] | ||
| Cost | 29,070 | 29,070 | 
| Accumulated Amortization | 14,525 | 13,188 | 
| Net Book Value | 14,545 | 15,882 | 
| Trade Names [Member] | ||
| Cost | 8,329 | 8,329 | 
| Accumulated Amortization | 6,090 | 5,379 | 
| Net Book Value | 2,239 | 2,950 | 
| Non-compete Agreements [Member] | ||
| Cost | 4,331 | 4,331 | 
| Accumulated Amortization | 4,331 | 4,320 | 
| Net Book Value | $ 0 | $ 11 | 
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- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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