Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Assets
Mortgage-backed securities, at fair value (including pledged assets of $17,377,453 and $17,012,472 at March 31, 2012 and December 31, 2011, respectively)	$ 18,323,972	$ 17,741,873
Cash and cash equivalents	715,745	347,045
Restricted cash	249,187	237,014
Unsettled purchased mortgage-backed securities, at fair value	1,815,658	49,630
Accrued interest receivable	63,265	63,025
Principal payments receivable	120,166	105,333
Debt security, held to maturity, at cost	15,000	15,000
Interest rate hedge asset	12
Other assets	30,283	27,799
Total assets	21,333,288	18,586,719
Liabilities and shareholders' equity
Repurchase agreements	16,556,630	16,162,375
Payable for unsettled securities	1,812,203	48,999
Accrued interest payable	3,387	4,596
Interest rate hedge liability	219,959	219,167
Dividend payable	69,889	69,141
Accounts payable and other liabilities	1,920	2,253
Total liabilities	18,663,988	16,506,531
Shareholders' equity:
Preferred stock, $.001 par value, 10,000,000 shares authorized, none outstanding at March 31, 2012 and December 31, 2011
Common stock, $.001 par value, 200,000,000 shares authorized, 97,779,404 and 76,823,220 shares issued and outstanding at March 31, 2012 and December 31, 2011, respectively	98	77
Additional paid-in capital	2,467,339	1,904,748
Retained earnings (accumulated deficit)	1,456	2,041
Accumulated other comprehensive income	200,407	173,322
Total shareholders' equity	2,669,300	2,080,188
Total liabilities and shareholders' equity	$ 21,333,288	$ 18,586,719