Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	$ 1,225	$ 888	$ 2,548	$ 2,870
Development and Leasing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	624	(6)	702	57
Loan Guarantee Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	23	40	209	121
Management Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	470	761	1,316	2,391
Marketing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees paid by unconsolidated joint ventures	$ 108	$ 93	$ 321	$ 301