SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS Common Shares (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	12 Months Ended
	Nov. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Common Stock [Member]
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)	2,250,000	9,510,000	2,250,000
Proceeds from Issuance of Common Stock	$ 45.0
Stock Issued During Period, Shares, Conversion of Units		334,000	11,000	365,000
At The Market Equity Program [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock		140.8
At The Market Equity Program [Member] | Common Stock [Member]
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)		6,100,000
Public Offering [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock		85.9
Public Offering [Member] | Common Stock [Member]
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)		3,500,000
Common Op Units Conversion To Common Shares [Member] | Common Stock [Member]
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Units		250,000
Restricted Stock [Member]
Class of Stock [Line Items]
Restricted Stock, Shares Canceled for Tax Withholding For Share Based Compensation		8,595
LTIP Units and Restricted Stock [Member]
Class of Stock [Line Items]
Allocated Share-based Compensation Expense		3.6	4.0	3.8