Fair value measurements (Tables)

6 Months Ended

Jun. 30, 2014

Fair Value Measurements [Abstract]

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

			As of June 30, 2014
(Amounts in thousands)			Total		Level 1		Level 2		Level 3
	Marketable securities		$	35,729	$	35,729	$	-	$	-
	Interest rate cap (included in other assets)			47		-		47		-
		Total assets	$	35,776	$	35,729	$	47	$	-
			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 June 30, 2014				As of December 31, 2013
		Carrying		Fair		Carrying		Fair
(Amounts in thousands)		Amount		Value		Amount		Value
Assets:
	Cash equivalents	$	303,433	$	303,433	$	184,796	$	184,796
Liabilities:
	Mortgages payable	$	1,034,289	$	1,037,000	$	1,049,959	$	1,072,000
	Leasing commissions (included in amounts due to Vornado)		41,279		41,000		42,924		43,000
		$	1,075,568	$	1,078,000	$	1,092,883	$	1,115,000