Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2013

Fair Value [Abstract]

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

		As of March 31, 2013
(Amounts in thousands)		Total		Level 1		Level 2		Level 3
	Marketable securities	$	34,460	$	34,460	$	-	$	-
		As of December 31, 2012
(Amounts in thousands)		Total		Level 1		Level 2		Level 3
	Marketable securities	$	31,206	$	31,206	$	-	$	-

Schedule Of Carrying Amounts And Fair Values Of Financial Instruments [Table Text Block]

			As of March 31, 2013				As of December 31, 2012
			Carrying		Fair		Carrying		Fair
(Amounts in thousands)			Amount		Value		Amount		Value
Assets:
	Cash equivalents	$	328,678	$	328,678	$	289,054	$	289,054
Liabilities:
	Mortgages payable	$	1,061,953	$	1,106,000	$	1,065,916	$	1,097,000
	Leasing commissions (included in Amounts due to Vornado)		45,189		45,000		45,803		46,000
		$	1,107,142	$	1,151,000	$	1,111,719	$	1,143,000