Derivatives Instruments and Hedging Activities - Summary of Outstanding Interest Rate Swaps (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Nov. 25, 2015	Sep. 16, 2015	Dec. 31, 2014
Derivative [Line Items]
Interest rate swap liabilities	$ 93,936,000			$ 194,196,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	1,200,000,000
Interest rate swap liabilities	84,695,000			194,196,000
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	$ 55,404,000			86,099,000
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] | 31 West 52nd Street [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	$ 237,600,000
Effective Dates	2007-12
Maturity Date	2017-12
Strike Rate	4.79%
Interest rate swap liabilities	$ 17,661,000			28,748,000
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	$ 11,630,000			19,158,000
Not Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Interest rate swap liabilities				$ 60,191,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Interest rate swap liabilities	9,241,000
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Interest Rate Swap [Member] | September Two Thousand Fifteen | Cash Flow Hedges [Member]
Derivative [Line Items]
Notional Amount	$ 1,000,000,000		$ 1,000,000,000
Strike Rate	1.79%
Interest rate swap liabilities	$ 9,204,000
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Interest Rate Swap [Member] | November Two Thousands And Fifteen | Cash Flow Hedges [Member]
Derivative [Line Items]
Notional Amount	$ 400,000,000	$ 400,000,000
Strike Rate	2.35%
Interest rate swap liabilities	$ 37,000
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Minimum | Interest Rate Swap [Member] | September Two Thousand Fifteen | Cash Flow Hedges [Member]
Derivative [Line Items]
Effective Dates	2015-12
Maturity Date	2015-12
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Minimum | Interest Rate Swap [Member] | November Two Thousands And Fifteen | Cash Flow Hedges [Member]
Derivative [Line Items]
Effective Dates	2020-12
Maturity Date	2021-12
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Maximum | Interest Rate Swap [Member] | September Two Thousand Fifteen | Cash Flow Hedges [Member]
Derivative [Line Items]
Effective Dates	2020-12
Maturity Date	2020-12