Business Acquisition Contingent Considerations Potential Payments

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- Definition

Compensation Expense, acquisition related

+ References

No definition available.

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- Definition

Holdback payment for prior acquisition

+ References

No definition available.

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- Details

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- Definition

Amount of long-term debt due within one year or within the normal operating cycle, if longer, assumed at the acquisition date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

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- Definition

The number of businesses acquired by the entity during the period.

+ References

No definition available.

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- Definition

The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

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Acquisitions (Details) (USD $)	12 Months Ended
Acquisitions (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	May 21, 2013
Business Acquisition [Line Items]
Acquisition, net of cash acquired	$ 0	$ 145,321,000	$ 0
Holdback payment for prior acquisition	3,353,000altr_Holdbackpaymentforprioracquisition	0altr_Holdbackpaymentforprioracquisition	0altr_Holdbackpaymentforprioracquisition
2013 Acquisitions [Member]
Business Acquisition [Line Items]
Acquisition, net of cash acquired		145,300,000
Number of Businesses Acquired		2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt					22,000,000
Avalon [Member]
Business Acquisition [Line Items]
Acquisition, net of cash acquired				8,000,000
Number of Businesses Acquired				1
Business Acquisition Contingent Considerations, Potential Payments				7,500,000
Compensation Expense, acquisition related	$ 1,900,000	$ 1,900,000	$ 1,900,000