Represents the amount of counter claim filed by entity.

No definition available.

Name:	agx_GainContingencyCounterClaimSoughtValue
Namespace Prefix:	agx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of damages sought by the plaintiff against the bond of the project.

+ References

No definition available.

+ Details

Name:	agx_LossContingencyDamagesSoughtAgainstBondValue
Namespace Prefix:	agx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the number of significant project locations involved in the lawsuit.

+ References

No definition available.

+ Details

Name:	agx_NumberOfSignificantProjectLocationsInvolvedInLawsuit
Namespace Prefix:	agx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the information pertaining to warranty provisions covering defects in equipment, materials etc.. after the completion of construction.

+ References

No definition available.

+ Details

Name:	agx_WarrantyPeriodForConstructionContracts
Namespace Prefix:	agx_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

+ Details

Name:	us-gaap_LossContingencyDamagesSoughtValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=agx_PPSEngineersIncClaimsLawsuitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationStatusAxis=us-gaap_PendingLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

CONTINGENCIES (Details) $ in Millions			12 Months Ended
CONTINGENCIES (Details) $ in Millions	Mar. 04, 2016 USD ($)	Feb. 01, 2016 USD ($) project	Jan. 31, 2017
Minimum
Loss Contingencies
Warranty period			9 months
Maximum
Loss Contingencies
Warranty period			24 months
PPS Engineers, Inc. claims lawsuit \| Pending Litigation
Loss Contingencies
Amount of damages sought by plaintiff		$ 0.9
Number of significant project locations involved in the lawsuit \| project		1
Damages sought against bond of the project		$ 2.5
Counter claim amount sought	$ 2.2