CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	66,890,711	66,601,909
Common stock, held in treasury	284,493	69,816