Statements Of Income (USD $) In Thousands, except Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Interest income:
Interest income on mortgage-backed securities	$ 110,125	$ 63,701	$ 310,248	$ 196,083
Interest income on short-term cash investments	380	323	1,051	898
Interest income	110,505	64,024	311,299	196,981
Interest expense	40,259	24,066	102,363	71,183
Net interest income	70,246	39,958	208,936	125,798
Other income:
Gain on sale of mortgage-backed securities	13,330	6,723	17,735	7,767
Operating expenses:
Management fee	3,572	2,321	10,195	6,700
Share based compensation	334	463	735	1,153
General and administrative	688	665	1,992	1,934
Total operating expenses	4,594	3,449	12,922	9,787
Net income	$ 78,982	$ 43,232	$ 213,749	$ 123,778
Earnings per share - common stock, basic	$ 1.04	$ 1.12	$ 3.05	$ 3.33
Earnings per share - common stock, diluted	$ 1.04	$ 1.11	$ 3.05	$ 3.32
Dividends per share	$ 1.00	$ 1.10	$ 3.00	$ 3.40
Weighted average shares outstanding	75,743,002	38,765,078	70,057,263	37,214,640