Mortgage and Mezzanine Loans Receivable (Narratives) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended	1 Months Ended			1 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013 NY 701 Seventh Avenue [Member]	Jan. 31, 2014 NY 701 Seventh Avenue [Member]	Oct. 31, 2012 NY 701 Seventh Avenue [Member]	Mar. 31, 2014 Other Mezzanine Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mezzanine Loan Ownership Percentage					25.00%
Percentage Of Participation In Mortgage Interest Sold			25.00%
Proceeds From Sale Of Participation In Mortgage Loan Receivable			$ 59,375
Other assets	290,544	351,488
Other liabilities	378,551	437,073	59,375	59,375
Prepayment Of Mezzanine Loan Receivable						30,000
Mezzanine Loan Receivable Maturity Date						January 2015
Mortgage and mezzanine loans receivable	$ 42,749	$ 170,972		$ 59,375
Mezzanine Loan Receivable Weighted Average Interest Rate	8.70%	11.00%
Mezzanine Loans Receiveable - Maturity Start Date	November 2014
Mezzanine Loans Receiveable - Maturity End Date	May 2016