2.4.0.840302 - Disclosure - Investments in Equipment and Leases, Net (Investment in Leases) (Details)truefalseIn Thousands, unless otherwise specifiedfalse1false USDfalsefalse$Duration_1_1_2013_To_6_30_2013http://www.sec.gov/CIK0000927569duration2013-01-01T00:00:002013-06-30T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDtruefalse$Duration_1_1_2013_To_6_30_2013_xxaay_InvestmentInEquipmentAndLeasesByTypeAxis_xxaay_OperatingLeasesMemberhttp://www.sec.gov/CIK0000927569duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseOperating Leases [Member]xxaay_InvestmentInEquipmentAndLeasesByTypeAxisxbrldihttp://xbrl.org/2006/xbrldixxaay_OperatingLeasesMemberxxaay_InvestmentInEquipmentAndLeasesByTypeAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDtruefalse$As_Of_6_30_2013_xxaay_InvestmentInEquipmentAndLeasesByTypeAxis_xxaay_AssetsHeldForSaleOrLeaseMemberhttp://www.sec.gov/CIK0000927569instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseAssets Held For Sale or Lease [Member]xxaay_InvestmentInEquipmentAndLeasesByTypeAxisxbrldihttp://xbrl.org/2006/xbrldixxaay_AssetsHeldForSaleOrLeaseMemberxxaay_InvestmentInEquipmentAndLeasesByTypeAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDtruefalse$As_Of_12_31_2012_xxaay_InvestmentInEquipmentAndLeasesByTypeAxis_xxaay_AssetsHeldForSaleOrLeaseMemberhttp://www.sec.gov/CIK0000927569instant2012-12-31T00:00:000001-01-01T00:00:00falsefalseAssets Held For Sale or Lease [Member]xxaay_InvestmentInEquipmentAndLeasesByTypeAxisxbrldihttp://xbrl.org/2006/xbrldixxaay_AssetsHeldForSaleOrLeaseMemberxxaay_InvestmentInEquipmentAndLeasesByTypeAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 3xxaay_LeasesDisclosureLineItemsxxaay_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Leases Disclosure [Line Items]2false 4xxaay_InvestmentInEquipmentAndLeasesxxaay_falsedebitinstantfalsefalsefalsefalsefalsetruefalsefalseperiodStartLabel1truefalsefalse31820003182USD$falsetruefalse2truefalsefalse31150003115USD$falsetruefalse3truefalsefalse6700067USD$falsetruefalse4truefalsefalse6700067USD$falsetruefalsexbrli:monetaryItemTypemonetaryTangible assets that are currently under operating or direct financing leases, or held in inventory as available for sale or re-lease.No definition available.false2Balance December 31, 20123false 4xxaay_InvestmentInEquipmentAndLeasesReclassificationsAdditionsAndDispositionsxxaay_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-37000-37falsefalsefalse2truefalsefalse-37000-37falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryInvestment in Equipment and Leases Reclassifications Additions and DispositionsNo definition available.false2Reclassifications, Additions/ Dispositions4false 4xxaay_InvestmentInEquipmentAndLeasesDepreciationAndAmortizationExpensexxaay_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-116000-116falsefalsefalse2truefalsefalse-116000-116falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryInvestment in Equipment and Leases Depreciation and Amortization ExpenseNo definition available.false2Depreciation/ Amortization Expense or Amortization of Leases5false 4xxaay_InvestmentInEquipmentAndLeasesxxaay_falsedebitinstantfalsefalsefalsefalsefalsefalsetruefalseperiodEndLabel1truefalsefalse30290003029USD$falsetruefalse2truefalsefalse29620002962USD$falsetruefalse3truefalsefalse6700067USD$falsetruefalse4truefalsefalse6700067USD$falsetruefalsexbrli:monetaryItemTypemonetaryTangible assets that are currently under operating or direct financing leases, or held in inventory as available for sale or re-lease.No definition available.false2Balance June 30, 2013falseInvestments in Equipment and Leases, Net (Investment in Leases) (Details) (USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.atel.com/role/DisclosureInvestmentsInEquipmentAndLeasesNetInvestmentInLeasesDetails45