2.2.0.7 true Property and Equipment (Details) (USD $) 0605 - Disclosure - Property and Equipment (Details) true false In Thousands false false 1 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ 2 Components of Property and Equipment 2 us-gaap_PropertyPlantAndEquipmentAbstract us-gaap true na duration No definition available. false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 3 Land and land rights 2 us-gaap_Land us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 true true false false 23108000 23108 false false false 2 true true false false 23108000 23108 false false false 3 true true false false 23108000 23108 false false false xbrli:monetaryItemType monetary Carrying amount as of the balance sheet date of real estate held for productive use. This excludes land held for sale. No authoritative reference available. false 4 Buildings 2 us-gaap_BuildingsAndImprovementsGross us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 146909000 146909 false false false 2 false true false false 146909000 146909 false false false 3 false true false false 152557000 152557 false false false xbrli:monetaryItemType monetary Carrying amount as of the balance sheet date of long-lived, depreciable assets that include building structures held for productive use including any addition, improvement, or renovation to the structure, such as interior masonry, interior flooring, electrical, and plumbing. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 5 Equipment and software 2 altr_EquipmentAndSoftware altr false debit instant Equipment and software. false false false false false false false false false false false verboselabel false 1 false true false false 210346000 210346 false false false 2 false true false false 210346000 210346 false false false 3 false true false false 213187000 213187 false false false xbrli:monetaryItemType monetary Equipment and software. No authoritative reference available. false 6 Office furniture and fixtures 2 us-gaap_FurnitureAndFixturesGross us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 24011000 24011 false false false 2 false true false false 24011000 24011 false false false 3 false true false false 20798000 20798 false false false xbrli:monetaryItemType monetary Carrying amount at the balance sheet date for long-lived, depreciable asset commonly used in offices and stores. Examples include desks, chairs, and store fixtures. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 7 Leasehold improvements 2 us-gaap_LeaseholdImprovementsGross us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 6819000 6819 false false false 2 false true false false 6819000 6819 false false false 3 false true false false 6930000 6930 false false false xbrli:monetaryItemType monetary Carrying amount at the balance sheet date of long-lived, depreciable asset that is an addition or improvement to assets held under lease arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 8 Construction in progress 2 us-gaap_ConstructionInProgressGross us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 1564000 1564 false false false 2 false true false false 1564000 1564 false false false 3 false true false false 1464000 1464 false false false xbrli:monetaryItemType monetary Carrying amount at the balance sheet date of long-lived asset under construction that include construction costs to date on capital projects that have not been completed and assets being constructed that are not ready to be placed into service. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 true 9 Property and equipment, at cost 2 us-gaap_PropertyPlantAndEquipmentGross us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 412757000 412757 false false false 2 false true false false 412757000 412757 false false false 3 false true false false 418044000 418044 false false false xbrli:monetaryItemType monetary Carrying amount at the balance sheet date for long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, physical structures, machinery, vehicles, furniture, computer equipment, construction in progress, and similar items. Amount does not include depreciation. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 10 Accumulated depreciation and amortization 2 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant No definition available. false false false false false false false false false false true negatedtotal false 1 false true false false -247325000 -247325 false false false 2 false true false false -247325000 -247325 false false false 3 false true false false -243528000 -243528 false false false xbrli:monetaryItemType monetary The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 -Subparagraph c Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 14 -Article 5 true 11 Property and equipment, net 2 us-gaap_PropertyPlantAndEquipmentNet us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 165432000 165432 false false false 2 false true false false 165432000 165432 false false false 3 false true false false 174516000 174516 false false false xbrli:monetaryItemType monetary Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, and production equipment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 13 -Subparagraph a -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 12 -Paragraph 5 -Subparagraph b, c Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 7 true 12 Property and Equipment (Textuals) 2 altr_PropertyAndEquipmentTextualsAbstract altr false na duration Property and Equipment. false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Property and Equipment. false 13 Depreciation expense 2 us-gaap_DepreciationAndAmortization us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 6400000 6400 false false false 2 false true false false 13504000 13504 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 14 Equipment and software 2 altr_EquipmentAndSoftware altr false debit instant Equipment and software. false false false false false false false false false false false verboselabel false 1 false true false false 210346000 210346 false false false 2 false true false false 210346000 210346 false false false 3 false true false false 213187000 213187 false false false xbrli:monetaryItemType monetary Equipment and software. No authoritative reference available. false 15 Net of accumulated amortization 2 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 247325000 247325 false false false 2 false true false false 247325000 247325 false false false 3 false true false false 243528000 243528 false false false xbrli:monetaryItemType monetary The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 -Subparagraph c Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 14 -Article 5 false 16 Assets Held under Capital Leases [Member] 0 na true na na No definition available. false true false false false false false false false false false http://altera.com/role/propertyandequipmentdetails false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false false 6 USD true false false false us-gaap_AssetsHeldUnderCapitalLeasesMember us-gaap_PropertyPlantAndEquipmentByTypeAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_AssetsHeldUnderCapitalLeasesMember us-gaap_PropertyPlantAndEquipmentByTypeAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 7 USD true false false false us-gaap_AssetsHeldUnderCapitalLeasesMember us-gaap_PropertyPlantAndEquipmentByTypeAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_AssetsHeldUnderCapitalLeasesMember us-gaap_PropertyPlantAndEquipmentByTypeAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 17 Components of Property and Equipment 2 us-gaap_PropertyPlantAndEquipmentAbstract us-gaap true na duration No definition available. false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 20 Equipment and software 2 altr_EquipmentAndSoftware altr false debit instant Equipment and software. false false false false false false false false false false false verboselabel false 1 false true false false 6500000 6500 false false false 2 false false false false 0 0 false false false 3 false true false false 8600000 8600 false false false xbrli:monetaryItemType monetary Equipment and software. No authoritative reference available. false 25 Accumulated depreciation and amortization 2 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant No definition available. false false false false false false false false false false true negatedtotal false 1 false true false false -9000000 -9000 false false false 2 false false false false 0 0 false false false 3 false true false false -6900000 -6900 false false false xbrli:monetaryItemType monetary The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 -Subparagraph c Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 14 -Article 5 true 27 Property and Equipment (Textuals) 2 altr_PropertyAndEquipmentTextualsAbstract altr false na duration Property and Equipment. false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Property and Equipment. false 29 Equipment and software 2 altr_EquipmentAndSoftware altr false debit instant Equipment and software. false false false false false false false false false false false verboselabel false 1 false true false false 6500000 6500 false false false 2 false false false false 0 0 false false false 3 false true false false 8600000 8600 false false false xbrli:monetaryItemType monetary Equipment and software. No authoritative reference available. false 30 Net of accumulated amortization 2 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant No definition available. false false false false false false false false false false false verboselabel false 1 true true false false 9000000 9000 false false false 2 false false false false 0 0 false false false 3 true true false false 6900000 6900 false false false xbrli:monetaryItemType monetary The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement. 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