Treasury Stock	12 Months Ended
Dec. 31, 2011
Treasruy Stock [Abstract]
Treasury Stock [Text Block]	Treasury Stock In July 2010, the Company’s board of directors approved a common stock purchase plan to purchase up to $40.0 million of its common stock. This plan has no expiration date. The Company purchased $12.0 million of its common stock in the year ended December 31, 2011, of which $11.9 million was attributed to the July 2010 purchase plan and $0.1 million was attributed to the July 2008 purchase plan. The Company expects to use the treasury stock to issue shares for stock option exercises, restricted stock grants and employee stock purchase plan stock purchases.

Treasury Stock

12 Months Ended

Dec. 31, 2011

Treasury Stock

In July 2010, the Company’s board of directors approved a common stock purchase plan to purchase up to $40.0 million of its common stock. This plan has no expiration date. The Company purchased $12.0 million of its common stock in the year ended December 31, 2011, of which $11.9 million was attributed to the July 2010 purchase plan and $0.1 million was attributed to the July 2008 purchase plan. The Company expects to use the treasury stock to issue shares for stock option exercises, restricted stock grants and employee stock purchase plan stock purchases.