CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable, allowance	$ 37,838	$ 12,505
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000	1,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	349,000	349,000
Common stock, shares issued	257,087	254,691
Common stock, shares outstanding	172,415	190,382
Treasury stock at cost, shares	84,672	63,951