Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Real estate, accumulated depreciation	$ 135,876	$ 127,745
Deferred financing costs, accumulated amortization	19,389	17,768
Intangible assets, accumulated amortization	6,511	4,564
Indebtedness, fair value	$ 411,963	$ 389,146
Series D cumulative redeemable preferred shares, par value	$ 0.01	$ 0.01
Series D cumulative redeemable preferred shares, shares authorized	4,000,000	4,000,000
Series D cumulative redeemable preferred shares, shares issued	4,000,000	2,600,000
Series D cumulative redeemable preferred shares, shares outstanding	4,000,000	2,600,000
Preferred shares, authorized	25,000,000	25,000,000
Cumulative redeemable preferred shares, shares issued	4,000,000
Common shares, par value	$ 0.03	$ 0.03
Common shares, shares authorized	200,000,000	200,000,000
Common shares, shares issued	82,289,029	71,447,437
Common shares, shares outstanding	541,825	71,447,437
Unvested restricted common share awards	541,825	369,500
7.75% Series A cumulative redeemable preferred shares
Preferred shares, authorized	4,760,000	4,760,000
Preferred shares, dividend rate	7.75%	7.75%
Cumulative redeemable preferred shares, liquidation preference	$ 25.00	$ 25.00
Cumulative redeemable preferred shares, shares issued	4,069,288	4,069,288
Cumulative redeemable preferred shares, shares outstanding	4,069,288	4,069,288
Preferred Shares, par value	$ 0.01	$ 0.01
8.375% Series B cumulative redeemable preferred shares
Preferred shares, authorized	4,300,000	4,300,000
Preferred shares, dividend rate	8.375%	8.375%
Cumulative redeemable preferred shares, liquidation preference	$ 25.00	$ 25.00
Cumulative redeemable preferred shares, shares issued	2,288,465	2,288,465
Cumulative redeemable preferred shares, shares outstanding	2,288,465	2,288,465
Preferred Shares, par value	$ 0.01	$ 0.01
8.875% Series C cumulative redeemable preferred shares
Preferred shares, authorized	3,600,000	3,600,000
Preferred shares, dividend rate	8.875%	8.875%
Cumulative redeemable preferred shares, liquidation preference	$ 25.00	$ 25.00
Cumulative redeemable preferred shares, shares issued	1,640,100	1,640,100
Cumulative redeemable preferred shares, shares outstanding	1,640,100	1,640,100
Preferred Shares, par value	$ 0.01	$ 0.01
Series E cumulative redeemable preferred shares
Preferred shares, authorized	4,000,000	4,000,000
Preferred Shares, par value	$ 0.01	$ 0.01