Consolidated Statements of Comprehensive Income - Equity Component [Domain] - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Interest income:
Mortgage-backed securities	$ 24,196	$ 26,995	$ 47,923	$ 53,897
Mortgage loans held for investment	331	723	703	1,462
Total interest income	24,527	27,718	48,626	55,359
Interest expense:
Repurchase agreements and FHLB advances	5,506	6,548	10,852	14,159
Non recourse collateralized financing	36	24	61	46
Total interest expense	5,542	6,572	10,913	14,205
Net interest income	18,985	21,146	37,713	41,154
Gain (loss) on derivative instruments, net	17,090	(23,074)	(8,233)	(36,496)
Gain (loss) on sale of investments, net	(1,491)	(477)	(183)	(3,784)
Fair value adjustments, net	20	88	59	119
Income from equity method investment	711	0	733	0
Other income, net	(99)	137	(88)	212
General and administrative expenses:
Compensation and benefits	(2,351)	(2,329)	(4,467)	(4,881)
Other general and administrative	(2,403)	(1,490)	(4,544)	(3,057)
Net income (loss)	30,462	(5,999)	20,990	(6,733)
Preferred Stock Dividends	(2,294)	(2,294)	(4,588)	(4,588)
Net income (loss) to common shareholders	28,168	(8,293)	16,402	(11,321)
Change in unrealized (loss) gain of available-for-sale investments	(42,027)	33,114	(18,722)	57,080
Reclassification adjustment for (gain) loss on sale of investments, net	1,491	477	183	3,784
Reclassification adjustment for de-designated cash flow hedges	857	1,608	1,914	3,896
Total other comprehensive (loss) income	(39,679)	35,199	(16,625)	64,760
Comprehensive (loss) income to common shareholders	$ (11,511)	$ 26,906	$ (223)	$ 53,439
Weighted average common shares - basic and diluted	54,574	54,711	54,687	54,669
Net income per common share - basic and diluted	$ 0.52	$ (0.15)	$ 0.30	$ (0.21)