REVENUE RECOGNITION - Remaining Unsatisfied Performance Obligations (Details) $ in Millions	3 Months Ended
Apr. 30, 2018 USD ($)
REVENUE RECOGNITION
Contract backlog amount	$ 289.5
Contract backlog (as percent)	91.00%
Revenues recognized related to performance obligations	$ 128.0
Revenues recognized that was included in contract liabilities	$ 24.3

The amount of transaction price allocated to performance obligation that has been recognized as revenue.

No definition available.

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- Definition

Percentage of remaining performance obligation to total remaining performance obligation not recognized as revenue.

+ References

No definition available.

+ Details

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- Definition

The amount of revenues recognized that was included in contract liabilities.

+ References

No definition available.

+ Details

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Namespace Prefix:	agx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- References

No definition available.

+ Details

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- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=84173487&loc=SL51747714-108306

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130556-203045

+ Details

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