REVENUES FROM CONTRACTS WITH CUSTOMERS (Details) - USD ($) $ in Millions	Jan. 31, 2023	Jan. 31, 2022
REVENUES FROM CONTRACTS WITH CUSTOMERS
Amounts of unpriced change orders included in transaction prices	11.6	7.5

Amounts of unpriced change orders included in transaction prices.

No definition available.

Name:	agx_NPricedChangeOrdersIncludedInTransactionPrices
Namespace Prefix:	agx_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant