Interest Receivable (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Interest receivable by investment category
Interest receivable	$ 36,680	$ 35,828
Total MBS
Interest receivable by investment category
Interest receivable	36,660	35,806
Fannie Mae.
Interest receivable by investment category
Interest receivable	14,509	13,760
Freddie Mac.
Interest receivable by investment category
Interest receivable	2,994	3,110
Ginnie Mae.
Interest receivable by investment category
Interest receivable	19	19
Non-Agency MBS
Interest receivable by investment category
Interest receivable	19,138	18,917
Money market and other investments
Interest receivable by investment category
Interest receivable	$ 20	$ 22