Fair Value Measurements Assets and Liabilities Measured on a Non-Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation adjustments to investments in unconsolidated joint ventures	$ 1,047	$ 0	$ 390
Fair Value, Significant Unobservable Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long Lived Real Estate Assets Fair Value Disclosure	3,730	5,494	6,658
Total losses	3,457	5,805	3,502
Long Lived Assets Initial Basis	7,187	11,299	10,160
Total Fair Value Measurements - Non-Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in unconsolidated joint ventures			$ 1,050