Restatement of Previously Issued Condensed Consolidated Financial Statements (Details 4) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Net cash provided by operating activities	$ 510,852	$ 207,714
Net change in short-term investments	(1,994,378)	(1,398,399)
Net change in repurchase agreements	4,083	(5,366)
Net cash used in investing activities	(866,892)	(824,477)
Change in due to parent and affiliates	(4,580)	5,554
Net cash provided by financing activities	391,893	613,646
As previously reported
Net cash provided by operating activities		199,470
Net change in short-term investments		(2,859,785)
Net change in repurchase agreements		1,473,393
Net cash used in investing activities		(812,470)
Change in due to parent and affiliates		1,791
Net cash provided by financing activities		609,883
Accounting for forward settling to be announced (TBA) security transactions | Adjustments
Net cash provided by operating activities		8,244
Net change in short-term investments		1,461,386
Net change in repurchase agreements		(1,473,393)
Net cash used in investing activities		(12,007)
Change in due to parent and affiliates		3,763
Net cash provided by financing activities		$ 3,763