Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Stockholders' equity:
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	260,000	260,000
Additional common stock, shares issued	213,183	164,117
Treasury stock, shares	1,512	1,512