Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts and accrued income receivable, allowances	$ 30,917	$ 30,504
Pledged securities included in debt securities	$ 105,849	$ 149,922
Preferred stock, par value	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	500	500
Preferred stock, outstanding	0	0
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, shares authorized	300,000	300,000
Common stock, shares outstanding	107,239	105,410