Indebtedness (Debt issuances and retirements) - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2014	May. 31, 2014	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Debt Instrument [Line Items]
Net loss on extinguishment of indebtedness			$ (14,070)	$ (197)	$ (18,357)
Secured Mortgage Notes [Member]
Debt Instrument [Line Items]
Prepaid secured mortgage indebtedness	$ 82,627	$ 120,000
Net loss on extinguishment of indebtedness					$ (4,287)
Total Company Equity [Member] | New York [Member]
Debt Instrument [Line Items]
Net loss on extinguishment of indebtedness			$ (12,333)