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Significant Accounting Policies - Concentrations of Credit Risk/Accounting Standards Updates (Details) $ in Billions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2018 USD ($) Tenant
Annualized rent | Customer concentration |  |
Concentration of Credit Risk |  |
Number of tenants (tenants) | Tenant |  | 1
Maximum percentage of annualized rent for any one tenant not individually disclosed (percent) (more than) | 5.00% | 5.00%
Annualized rent | 1515 Broadway | Customer concentration |  |
Concentration of Credit Risk |  |
Percentage of concentration (percent) | 5.80% |
Annualized rent | 11 Madison Avenue | Customer concentration |  |
Concentration of Credit Risk |  |
Percentage of concentration (percent) | 7.30% |
Annualized rent | 1185 Avenue of the Americas | Customer concentration |  |
Concentration of Credit Risk |  |
Percentage of concentration (percent) | 7.20% |
Annualized rent | 420 Lexington Avenue | Customer concentration |  |
Concentration of Credit Risk |  |
Percentage of concentration (percent) | 6.40% |
Annualized rent | 1 Madison Ave | Customer concentration |  |
Concentration of Credit Risk |  |
Percentage of concentration (percent) | 5.70% |
Tenant 1 | Annualized rent | Customer concentration |  |
Concentration of Credit Risk |  |
Percentage of concentration (percent) |  | 8.20%
1515 Broadway | Accounting Standards Update 2017-05 |  |
Concentration of Credit Risk |  |
Gain on disposal | $ |  | $ 0.6

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