Consolidated Statements of Income (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Interest income:
Interest income on mortgage-backed securities	$ 115,115	$ 128,720	$ 239,356	$ 241,480
Interest income on short-term cash investments	359	441	801	773
Total interest income	115,474	129,161	240,157	242,253
Interest expense	52,079	46,169	105,356	87,278
Net interest income	63,395	82,992	134,801	154,975
Operating expenses:
Management fee	4,714	4,312	9,434	8,154
Share based compensation	627	425	1,256	854
General and administrative	1,602	1,316	2,971	2,229
Total operating expenses	6,943	6,053	13,661	11,237
Other income:
Net gain on sale of mortgage-backed securities	8,802	12,205	11,302	14,710
Net gain on futures contracts	5,485		5,536
Total other income	14,287	12,205	16,838	14,710
Net income	70,739	89,144	137,978	158,448
Dividends on preferred stock	5,480		10,960
Net income available to common shareholders	$ 65,259	$ 89,144	$ 127,018	$ 158,448
Earnings per share - common stock, basic	$ 0.66	$ 0.91	$ 1.29	$ 1.80
Earnings per share - common stock, diluted	$ 0.66	$ 0.91	$ 1.29	$ 1.80
Dividends per share of common stock	$ 0.70	$ 0.90	$ 1.40	$ 1.80
Weighted average common shares outstanding, basic	98,830,054	97,969,074	98,828,827	87,789,596
Weighted average common shares outstanding, diluted	98,830,054	97,969,074	98,828,827	87,789,596