Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	230	230
Common stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	200,000	200,000
Common stock, outstanding shares	85,543	70,950
Class A common stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	30,000	30,000
Common stock, outstanding shares	0	9,402