Derivative Instruments and Hedging Activities - Summary of Outstanding Interest Rate Swaps (Details) - USD ($)	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Interest rate swap liabilities	$ 102,577,000	$ 93,936,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	1,000,000,000
Interest rate swap liabilities	51,722,000	84,695,000
Not Designated as Hedging Instrument [Member] | One Market Plaza [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	$ 840,000,000
Maturity Date	2017-08
Strike Rate	5.02%
Interest rate swap liabilities	$ 42,061,000	55,404,000
Not Designated as Hedging Instrument [Member] | One Market Plaza [Member] | Minimum | Interest Rate Swap [Member]
Derivative [Line Items]
Effective Dates	2007-08
Not Designated as Hedging Instrument [Member] | One Market Plaza [Member] | Maximum | Interest Rate Swap [Member]
Derivative [Line Items]
Effective Dates	2012-08
Not Designated as Hedging Instrument [Member] | 900 Third Avenue [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	$ 162,000,000
Effective Dates	2007-11
Maturity Date	2017-11
Strike Rate	4.78%
Interest rate swap liabilities	$ 9,661,000	11,630,000
Not Designated as Hedging Instrument [Member] | 31 West 52nd Street [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Interest rate swap liabilities		17,661,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Interest rate swap liabilities	50,855,000	9,241,000
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Interest Rate Swap [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Notional Amount	1,000,000,000
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Interest Rate Swap September Two Thousand Fifteen [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Notional Amount	$ 1,000,000,000
Effective Dates	2015-12
Strike Rate	1.79%
Interest rate swap liabilities	$ 47,246,000	9,204,000
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Interest Rate Swap November Two Thousand Fifteen [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Notional Amount	$ 400,000,000
Effective Dates	2020-12
Maturity Date	2021-12
Strike Rate	2.35%
Interest rate swap liabilities	$ 3,609,000	$ 37,000
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Minimum | Interest Rate Swap September Two Thousand Fifteen [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Maturity Date	2020-12
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Maximum | Interest Rate Swap September Two Thousand Fifteen [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Maturity Date	2022-12