CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Accounts receivable, allowance	$ 10,095	$ 7,959
Treasury stock - Common stock, Shares	65,806	55,597
Common Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, Authorized	1,600,000	1,600,000
Common stock, Shares issued	188,388	176,378
Common stock, Shares outstanding	122,581	120,781
Common Class B
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, Authorized	400,000	400,000
Common stock, Shares issued	12,800	12,800
Common stock, Shares outstanding	12,800	12,800