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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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Represents the maximum percentage of concentration risk that is not individually disclosed.

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Represents the number of tenants to whom the facility is leased.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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