CONSOLIDATED BALANCE SHEETS (Parenthetical)	Dec. 31, 2011	Dec. 31, 2010
CONSOLIDATED BALANCE SHEETS
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	75,833,696	75,244,553
Treasury stock, shares	25,221,481	21,071,582