XML 25 R33.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Commitments and Contingencies (Details) (USD $) |  |  | 3 Months Ended |  | 12 Months Ended | 3 Months Ended
--- | --- | --- | --- | --- | --- | ---
Mar. 31, 2014 | Dec. 31, 2013 | Mar. 31, 2014 Lexington Avenue Property [Member] | Mar. 31, 2014 Paramus Property [Member] Tenant Occupant [Member] Ikea [Member] | Dec. 31, 2001 Paramus Property [Member] Tenant Occupant [Member] Ikea [Member] acre | Dec. 31, 2021 Paramus Property [Member] Tenant Occupant [Member] Ikea [Member] Scenario Forecast [Member] | Mar. 31, 2014 Flushing Property [Member] | Mar. 31, 2014 General Liability [Member] | Mar. 31, 2014 All Risk Property And Rental Value [Member] | Mar. 31, 2014 Terrorism Coverage Including Nbcr [Member] | Mar. 31, 2014 NBCR [Member]
Insurance [Abstract] |  |  |  |  |  |  |  |  |  |  |
Mortgage loans, recourse |  |  | $ 75,000,000 |  |  |  |  |  |  |  |
Mortgages payable | 1,035,022,000 | 1,049,959,000 | 320,000,000 | 68,000,000 |  |  |  |  |  |  |
Insurance Maximum Coverage Per Incident |  |  |  |  |  |  |  | 300,000,000 | 1,700,000,000 | 1,700,000,000 |
Deductible |  |  |  |  |  |  |  |  |  |  | 275,000
Self Insured Responsibility (in percentage) |  |  |  |  |  |  |  |  |  |  | 15.00%
Federal Government Responsibility (in percentage) |  |  |  |  |  |  |  |  |  |  | 85.00%
Flushing Property [Abstract] |  |  |  |  |  |  |  |  |  |  |
Non-refundable purchase deposit |  |  |  |  |  |  | 1,875,000 |  |  |  |
Indemnification Sought by Tenant |  |  |  |  |  |  | 50,000,000 |  |  |  |
Paramus Property [Abstract] |  |  |  |  |  |  |  |  |  |  |
Area Of Land (in acre) |  |  |  |  | 30.3 |  |  |  |  |  |
Property purchase option exercisable be leasee with purchase option in 2021 |  |  |  |  |  | 75,000,000 |  |  |  |  |
Mortgages payable | 1,035,022,000 | 1,049,959,000 | 320,000,000 | 68,000,000 |  |  |  |  |  |  |
Fixed interest rate on the debt (in percentage) |  |  |  | 2.90% |  |  |  |  |  |  |
Triple-net rent, annual amount |  |  |  | 700,000 |  |  |  |  |  |  |
Purchase option exercised, proceeds from sale of land |  |  |  |  |  | 7,000,000 |  |  |  |  |
Purchase option excercised, gain on sale of land |  |  |  |  |  | 60,000,000 |  |  |  |  |
Purchase option not excercised amount included in triple net rent over remainder of lease |  |  |  |  |  | 68,000,000 |  |  |  |  |
Loan Amortization Period |  |  |  |  |  | 20 years |  |  |  |  |
Letters Of Credit [Abstract] |  |  |  |  |  |  |  |  |  |  |
Standby letters of credit, issued and outstanding | $ 3,308,000 |  |  |  |  |  |  |  |  |  |

X
- Definition The deductible owed by our wholly owned insurance subsidiary in the event of a covered loss + References No definition available. + Details
Name: | alx_Deductible
Namespace Prefix: | alx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The percentage of the covered portion of a loss above the deductible for which the Federal Government is responsible for covered losses + References No definition available. + Details
Name: | alx_FederalGovernmentResponsibility
Namespace Prefix: | alx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | alx_FlushingPropertyAbstract
Namespace Prefix: | alx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Insurance maximum coverage limit per incident + References No definition available. + Details
Name: | alx_InsuranceMaximumCoveragePerIncident
Namespace Prefix: | alx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | alx_LettersOfCreditAbstract
Namespace Prefix: | alx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition In the event the tenant does not exercise its purchase option, the period over which the tenant's debt service portion of its rent must be sufficient to fully amortize the loan on the property + References No definition available. + Details
Name: | alx_LoanAmortizationPeriod
Namespace Prefix: | alx_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Indemnification sought by the tenant for legal action brought against the tenant by a 3rd party. + References No definition available. + Details
Name: | alx_LossContingencyIndemnificationSought
Namespace Prefix: | alx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of loan that will become recourse in case of a substantial casualty + References No definition available. + Details
Name: | alx_MortgageLoanConvertedToRecourse
Namespace Prefix: | alx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | alx_ParamusPropertyAbstract
Namespace Prefix: | alx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Lease with purchase option to be exercised by lessee. + References No definition available. + Details
Name: | alx_PropertyPurchaseOptionExcercisableByLessee
Namespace Prefix: | alx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cash inflow from the sale of land held for use in case the purchase option is exercised by leasee. + References No definition available. + Details
Name: | alx_PurchaseOptionExercisedProceedsFromSaleOfLandHeldForUse
Namespace Prefix: | alx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount to be amortized over the remainder of the lease term if the purchase option is not exercised. + References No definition available. + Details
Name: | alx_PurchaseOptionNotExcercisedAmountIncludedInTripleNetRentOverRemainderOfLease
Namespace Prefix: | alx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The percentage of the covered portion of a loss above the deductible for which our wholly owned insurance subsidiary is responsible for covered losses + References No definition available. + Details
Name: | alx_SelfInsuredResponsibility
Namespace Prefix: | alx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Triple-net rent, annual amount + References No definition available. + Details
Name: | alx_TripleNetRentAnnualAmount
Namespace Prefix: | alx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Area of land held. + References No definition available. + Details
Name: | us-gaap_AreaOfLand
Namespace Prefix: | us-gaap_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition The effective interest rate at the end of the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateAtPeriodEnd
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of difference between the carrying amount and the sales price of real estate properties sold as part of discontinued operations. + References No definition available. + Details
Name: | us-gaap_GainLossOnDispositionOfRealEstateDiscontinuedOperations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_InsuranceAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 13, 16 -Article 9 + Details
Name: | us-gaap_NotesPayable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition This element represents money paid in advance to protect the provider of a product or service, such as a lessor, against damage or nonpayment by the buyer or tenant (lessee) during the term of the agreement. Such damages may include physical damage to the property, theft of property, and other contractual breaches. Security deposits held may be interest or noninterest bearing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.15(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_SecurityDepositLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant