Interim Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
Current assets:
Allowance for Doubtful Accounts Receivable, Current	$ 12,520	$ 11,536
Shareholders' equity:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	44,786,011	44,786,011
Common stock, shares outstanding	31,584,112	32,425,315
Treasury stock, shares	13,201,899	12,360,696