Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Stockholders' equity:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000	2,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	250,000	250,000
Common stock, shares issued	124,375	116,703
Common stock, shares outstanding	122,731	115,392