CONSOLIDATED BALANCE SHEET PARENTHETICAL (USD $)	Dec. 31, 2012	Dec. 31, 2011
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	40,792,449	39,840,838
Common stock, shares outstanding	37,221,344	36,278,206
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0