Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Pledged securities included in debt securities	$ 118,156	$ 105,849
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	105,689	107,239