Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Investments in real estate, variable interest entities	$ 65,446	$ 21,423
Restricted cash held in escrows, variable interest entities	6,811	1,101
Allowances on accounts receivable	474	374
Lease intangibles, variable interest entities	20,537	3,485
Mortgage loans payable, variable interest entities	66,085	23,184
Notes payable, variable interest entities	845	876
Accounts payable and accrued liabilities, variable interest entities	5,106	1,347
Below market lease intangibles, variable interest entities	$ 605	$ 51
Series D Cumulative Redeemable Preferred Shares, liquidation preference	$ 25	$ 25
Series D Cumulative Redeemable Preferred Shares, shares authorized	5,060,000	5,060,000
Series D Cumulative Redeemable Preferred Shares, shares issued	4,820,000	4,820,000
Series D Cumulative Redeemable Preferred Shares, shares outstanding	4,820,000	4,820,000
Common Shares, par value	$ 1	$ 1
Common Shares, unlimited shares authorized
Common Shares, shares issued	33,638,757	33,018,711
Common Shares, shares outstanding	33,638,757	33,018,711