Debt Instrument Covenant Compliance Aggregate Commitments

No definition available.

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Namespace Prefix:	alg_
Data Type:	xbrli:monetaryItemType
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- Definition

Debt Instrument Covenant Compliance Maximum Increase Amount Of Aggregate Commitments

+ References

No definition available.

+ Details

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Namespace Prefix:	alg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt and capital lease obligations including current maturities.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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- Details

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- Details

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- Details

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- Details

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- Details

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Debt (Narrative) (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014	May. 13, 2014	May. 12, 2014
Debt Instrument [Line Items]
Total debt	$ 203,542,000	$ 190,575,000
Amended and Restated Revolving Credit Agreement \| Bank revolving credit facility
Debt Instrument [Line Items]
Aggregate commitments	250,000,000
Maximum amount of additional aggregate commitments (Up to $50,000,000)	50,000,000
Total debt	203,000,000
Available borrowings	45,200,000
Amended and Restated Revolving Credit Agreement \| Standby Letters of Credit \| Bank revolving credit facility
Debt Instrument [Line Items]
Amount of capacity	$ 1,800,000
Amended and Restated Revolving Credit Agreement \| Specialized Industries LP \| Revolving Credit Facility
Debt Instrument [Line Items]
Amount of line of credit			$ 250,000,000	$ 100,000,000