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SPECIAL PURPOSE ENTITIES (Details) - VIE - USD ($) $ in Millions | 12 Months Ended
--- | ---
Jan. 31, 2021 | Jan. 31, 2020
Variable Interest Entity |  |
Gain on grant of utility easement | $ 2.2 |
Cost of property, plant and equipment | $ 7.5 | $ 6.9

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- Definition Amount of costs incurred related to activities to develop a gas-fired power plant to get a fixed asset ready for operation. + References No definition available. + Details
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Namespace Prefix: | agx_
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Balance Type: | debit
Period Type: | duration

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- Definition Represents gain (loss) on grant related to the granting of a utility easement. + References No definition available. + Details
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Namespace Prefix: | agx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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- Details
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