CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS, (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ (15,030,000)	$ (7,193,000)
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Stock based compensation and equity plan amortization	323,000	359,000
Realized and unrealized (gains) losses on mortgage-backed securities	112,642,000	29,463,000
Derivative, Gain (Loss) on Derivative, Net	(27,210,000)	6,073,000
Changes in operating assets and liabilities
Accrued interest receivable	(327,000)	(2,491,000)
Other assets	(269,000)	(212,000)
Accrued interest payable	705,000	342,000
Other liabilities	6,716,000	(2,563,000)
Due to affiliates	(141,000)	124,000
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	77,409,000	23,902,000
From mortgage-backed securities investments
Purchases	(1,995,208,000)	(3,692,066,000)
Sales	1,757,652,000	3,064,979,000
Principal repayments	180,169,000	155,303,000
Proceeds From Sale Of Federal Home Loan Bank Stock	0	3,000
Payments on net settlement of to-be-announced securities	12,493,000	(5,591,000)
Purchase of interest rate swaptions, net of margin cash received	(14,768,000)	0
NET CASH USED IN INVESTING ACTIVITIES	(30,126,000)	(477,372,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from repurchase agreements	26,040,287,000	25,243,560,000
Principal payments on repurchase agreements	(26,124,219,000)	(24,758,809,000)
Cash dividends	(33,370,000)	(28,902,000)
Proceeds From Issuance Of Common Stock, net of issuance costs	0	122,857,000
Payments For Repurchase Of Common Stock	7,681,000	0
NET CASH PROVIDED BY FINANCING ACTIVITIES	(124,983,000)	578,706,000
NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(77,700,000)	125,236,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, beginning of period	246,712,000	94,425,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, end of period	169,012,000	219,661,000
Cash paid during the period for:
Interest Paid	31,023,000	15,136,000
SUPPLEMENTAL DISCLOSURES OF NONCASH FINANCING ACTIVITIES:
Securities acquired settled in later period	0	273,689,000
Securities Sold Settled In Later Period	0	0
Interest Rate Swaption [Member]
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Derivative, Gain (Loss) on Derivative, Net	(4,434,000)	0
Swap [Member]
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Derivative, Gain (Loss) on Derivative, Net	(12,805,000)	3,689,000
TBA Contracts [Member]
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Derivative, Gain (Loss) on Derivative, Net	$ (9,971,000)	$ 2,384,000