Fair value measurements (Tables)

3 Months Ended

Mar. 31, 2014

Fair Value Measurements [Abstract]

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

			As of March 31, 2014
(Amounts in thousands)			Total		Level 1		Level 2		Level 3
	Marketable securities		$	33,363	$	33,363	$	-	$	-
	Interest rate cap (included in other assets)			242		-		242		-
		Total assets	$	33,605	$	33,363	$	242	$	-
			As of December 31, 2013
(Amounts in thousands)			Total		Level 1		Level 2		Level 3
		Marketable securities	$	31,522	$	31,522	$	-	$	-

Fair Value, by Balance Sheet Grouping [Table Text Block]

		As of March 31, 2014				As of December 31, 2013
		Carrying		Fair		Carrying		Fair
(Amounts in thousands)		Amount		Value		Amount		Value
Assets:
	Cash equivalents	$	341,294	$	341,294	$	184,796	$	184,796
Liabilities:
	Mortgages payable	$	1,035,022	$	1,055,000	$	1,049,959	$	1,072,000
	Leasing commissions (included in Amounts due to Vornado)		42,102		42,000		42,924		43,000
		$	1,077,124	$	1,097,000	$	1,092,883	$	1,115,000