Real Estate (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended			12 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Consolidated Rental Properties [Member]	Dec. 31, 2013 Consolidated Rental Properties [Member]	Sep. 30, 2014 Land [Member]
Land parcels acquired			2
Properties acquired			4		4
Property Units Acquired			1,080		1,080
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$ 404,400		$ 404,400		$ 375,610		$ 28,790
Disposed Properties			4		4
Disposed Units			1,317		1,317
Proceeds From Sale Of Property			227,602		197,100	4,500,000	30,502
Net gain on sales of real estate properties	113,641	0	128,544	0
Net gain (loss) on sales of land parcels	$ 1,052	$ (2,437)	$ 1,846	$ 12,179
land parcel disposed			2