Summary Of Significant Accounting Policies (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
Accounting Policies [Abstract]
Total interest costs incurred			$ 85,740	$ 91,208
Interest capitalized			(15,968)	(10,894)
Interest expense	23,422	25,762	69,772	80,314
Cash paid for interest, net of amounts capitalized			69,112	85,240
Cash paid for income taxes			328	408
Mortgage loans assumed with acquisition			68,282	0
DownREIT operating partnership units issued with acquisition			65,348	0
Mortgage loan refinanced			11,500	0
Repayment of note payable with public funding/related construction-in-progress offset			10,000	0
Shares issued under dividend reinvestment plan			$ 1,355	$ 1,325