Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	$ 566	$ 715
Development Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	8	69
Loan Guarantee Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	40	40
Management and Leasing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	409	496
Marketing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	$ 109	$ 110