Equity Transactions Narrative (Details) (USD $)	3 Months Ended					0 Months Ended	3 Months Ended				3 Months Ended	1 Months Ended		12 Months Ended		7 Months Ended		1 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Common Stock [Member]	Dec. 31, 2011 Common Stock [Member]	Nov. 30, 2004 Common Stock [Member]	Apr. 27, 2012 Common Stock [Member] Dividend Paid [Member]	Mar. 31, 2011 Common OP Units [Member]	Mar. 31, 2012 S-3 - Total [Member] Common Stock [Member]	May 31, 2009 S-3 - Total [Member] Common Stock [Member]	May 31, 2009 Form S-3 - May 2009 [Member] Common Stock [Member]	Mar. 31, 2012 Form S-3 - May 2011 [Member] Common Stock [Member]	Jan. 31, 2011 Common Stock Purchase Agreement [Member] Common Stock [Member]	Aug. 31, 2010 Common Stock Purchase Agreement [Member] Common Stock [Member]	Dec. 31, 2011 Preferred OP Units [Member] Common Stock [Member]	Jun. 30, 2011 Preferred OP Units [Member] Common Stock [Member]	Dec. 31, 2011 Preferred OP units before June 2013 [Member] Common Stock [Member]	Dec. 31, 2011 Preferred OP units after June 2013 [Member] Common Stock [Member]	Jan. 31, 2012 Registered public offering [Member] Common Stock [Member]	Mar. 31, 2012 Mortgages [Member] Mortgage - Florida Properties [Member]	Dec. 31, 2011 Mortgages [Member] Mortgage - Florida Properties [Member]
Class of Stock [Line Items]
Authorized to be repurchased (in shares)					1,000,000
Remaining number of shares authorized to be repurchased (in shares)				400,000
Conversion of Common OP Units to common stock (in shares)							3,370
Proposed offering amount from issuing common stock, preferred stock, and debt securities									$ 300,000,000
Common stock, draw down of shares on ATM (in shares)										1,600,000
New shares issued (in shares)											40,524	915,827						4,600,000
Weighted average sale price (in dollars per share)								$ 37.22				$ 32.76						$ 35.50
Proceeds from issuance of common stock	157,461,000	29,799,000						1,500,000				30,000,000						156,000,000
Purchase commitment of common stock, amount													100,000,000
Purchase committment of common stock (in shares)													3,889,493
Preferred OP units issued														45,500,000
Preferred OP unit, conversion price (in dollars per share)															$ 41
Preferred Operating Partnerhsip units, par value (in dollars per share)															$ 100
Preferred OP unit return rate																5.10%	6.00%
Proceeds from common stock used to extinguish debt																		123,500,000
Proceeds from common stock used to purchase property																		25,000,000
Debt Instrument, Face Amount																			19,000,000	17,000,000
Dividends per common share:	$ 0.63	$ 0.63	$ 0.63
Dividends, Common Stock, Cash Paid						$ 18,000,000