Derivative Instruments and Hedging Activities - Additional Information (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) Derivative	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) Derivative	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Fair value of derivative obligations to be settled	$ 1,588,000		$ 1,588,000
Change in value of interest rate swaps	$ (4,041,000)	$ (11,747,000)	$ (9,000)	$ (41,614,000)
Number of derivative instruments | Derivative	0		0
Designated as Hedging Instrument [Member] | 1633 Broadway [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Aggregate notional amount					$ 400,000,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Change in value of interest rate swaps	$ (4,041,000)	(11,747,000)	$ (9,000)	(41,614,000)
Estimated accumulated other comprehensive income (loss) reclassified to interest expense in the next twelve months			4,259,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | 1633 Broadway [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Aggregate notional amount	1,000,000,000		1,000,000,000
Designated as Hedging Instrument [Member] | Interest Rate Swap March Two Thousand Seventeen [Member] | 1633 Broadway [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Aggregate notional amount	$ 400,000,000		400,000,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative liability fair Value					$ 21,227,000
Unrealized gains on interest rate swaps		$ 10,073,000	$ 1,802,000	$ 16,933,000