CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Equity:
Preferred shares, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred shares, authorized shares (in shares)	100,000,000	100,000,000
Common shares, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common shares, authorized shares (in shares)	400,000,000	400,000,000
Common shares, shares issued (in shares)	155,419,094	154,938,351
Series B | Cumulative Redeemable
Equity:
Preferred shares liquidation preference	$ 68,522	$ 68,522
Preferred shares, shares issued (in shares)	2,740,874	2,740,874
Preferred shares, shares outstanding (in shares)		2,740,874
Series C | Cumulative Convertible
Equity:
Preferred shares liquidation preference	96,770	98,510
Preferred shares, shares issued (in shares)	1,935,400	1,970,200
Preferred shares, shares outstanding (in shares)	1,935,400	1,970,200
Series D | Cumulative Redeemable
Equity:
Preferred shares liquidation preference	$ 155,000	$ 155,000
Preferred shares, shares issued (in shares)	6,200,000	6,200,000
Preferred shares, shares outstanding (in shares)	6,200,000	6,200,000