XML 71 R38.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Property and Equipment - Additional Information (Detail) (USD $) | 12 Months Ended
--- | ---
Sep. 30, 2014 | Sep. 30, 2013
Property, Plant and Equipment [Abstract] |  |
Property and equipment (fully depreciated assets) | $ 6,190,000 | $ 6,772,000

X
- Definition Property and equipment (fully depreciated assets). + References No definition available. + Details
Name: | genc_PropertyAndEquipmentFullyDepreciatedAssets
Namespace Prefix: | genc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration