CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	39,599,374	39,439,115
Common stock, shares outstanding	35,635,357	37,907,575
Treasury stock, shares	3,964,017	1,531,540