Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 58,386	$ (60,955)	$ (296,525)	$ (358,586)
Other comprehensive income (loss):
Reclassification adjustment for realized gain on sale of available for sale Agency Securities	(9,468)	(4,569)	(138,802)	(1,615)
Reclassification adjustment for credit loss expense on available for sale Agency Securities	0	0	1,012	0
Net unrealized gain (loss) on available for sale Agency Securities	13,002	93,910	(17,486)	451,173
Other comprehensive income (loss)	3,534	89,341	(155,276)	449,558
Comprehensive Income (Loss)	$ 61,920	$ 28,386	$ (451,801)	$ 90,972