CONSOLIDATED BALANCE SHEETS CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable, allowance for doubtful accounts	$ 10,322	$ 6,103
Common stock, par value, (in dollar per share)	$ 0.008	$ 0.008
Common stock, authorized shares (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	58,055,586	57,578,431
Treasury stock, shares (in shares)	8,184,787	7,779,645