Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Deferred financing costs, accumulated amortization	$ 11,154	$ 9,943
Intangible assets, accumulated amortization	2,057	1,777
Indebtedness, fair value	$ 145,041	$ 152,494
Common shares, par value	$ 0.03	$ 0.03
Common shares, shares authorized	200,000,000	200,000,000
Common shares, shares issued	38,197,648	35,300,190
Common shares, shares outstanding	38,197,648	35,300,190
7.75% Series A Cumulative Redeemable Preferred Shares [Member]
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, shares authorized	25,000,000	25,000,000
Cumulative redeemable preferred shares, liquidation preference	$ 25	$ 25
Cumulative redeemable preferred shares, shares issued	2,760,000	2,760,000
Cumulative redeemable preferred shares, shares outstanding	2,760,000	2,760,000
8.375% Series B Cumulative Redeemable Preferred Shares [Member]
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, shares authorized	25,000,000	25,000,000
Cumulative redeemable preferred shares, liquidation preference	$ 25	$ 25
Cumulative redeemable preferred shares, shares issued	2,258,300	2,258,300
Cumulative redeemable preferred shares, shares outstanding	2,258,300	2,258,300
8.875% Series C Cumulative Redeemable Preferred Shares [Member]
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, shares authorized	25,000,000	25,000,000
Cumulative redeemable preferred shares, liquidation preference	$ 25	$ 25
Cumulative redeemable preferred shares, shares issued	1,600,000	1,600,000
Cumulative redeemable preferred shares, shares outstanding	1,600,000	1,600,000