Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Common shares, par value, per share	$ 0.01	$ 0.01
Common shares, authorized	100,000	100,000
Common shares, issued	94,927	87,377
Common shares, outstanding	91,957	84,517
Treasury shares, at cost	12,100	12,509