CONSOLIDATED STATEMENTS OF CASH FLOWS, (Unaudited) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ (44,387,000)	$ 2,007,000	$ 1,979,000
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Stock based compensation and equity plan amortization	492,000	535,000	605,000
Realized and unrealized (gains) losses on mortgage-backed securities	140,957,000	75,769,000	51,078,000
Derivative, Gain (Loss) on Derivative, Net	(4,052,000)	870,000	(7,017,000)
Changes in operating assets and liabilities
Accrued interest receivable	1,203,000	(2,932,000)	(3,022,000)
Other assets	(3,000)	(3,000)	80,000
Accrued interest payable	(71,000)	4,690,000	963,000
Other liabilities	4,000	3,841,000	2,279,000
Due to affiliates	(143,000)	231,000	101,000
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	94,000,000	85,008,000	47,046,000
From mortgage-backed securities investments
Purchases	(3,893,828,000)	(6,499,153,000)	(3,172,001,000)
Sales	3,885,817,000	5,335,583,000	2,002,813,000
Principal repayments	373,934,000	365,166,000	254,607,000
Proceeds From Sale Of Federal Home Loan Bank Stock	0	3,000	3,750,000
Payments on net settlement of to-be-announced securities	7,292,000	(5,242,000)	(1,401,000)
Purchase of interest rate swaptions, net of margin cash received	(6,805,000)	(1,138,000)	(704,000)
NET CASH USED IN INVESTING ACTIVITIES	380,020,000	(802,505,000)	(911,528,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from repurchase agreements	52,096,292,000	54,481,746,000	32,375,195,000
Principal payments on repurchase agreements	(52,605,026,000)	(53,741,665,000)	(31,380,303,000)
Principal Payments On Federal Home Loan Bank Advances	0	0	187,500,000
Cash dividends	(59,312,000)	(67,904,000)	(36,772,000)
Proceeds From Issuance Of Common Stock, net of issuance costs	0	197,607,000	118,328,000
Payments For Repurchase Of Common Stock	26,423,000	0	0
NET CASH PROVIDED BY FINANCING ACTIVITIES	(594,469,000)	869,784,000	888,948,000
NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(120,449,000)	152,287,000	24,466,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, beginning of period	246,712,000	94,425,000	69,959,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, end of period	126,263,000	246,712,000	94,425,000
Cash paid during the period for:
Interest Paid	70,431,000	36,981,000	14,641,000
SUPPLEMENTAL DISCLOSURES OF NONCASH FINANCING ACTIVITIES:
Securities Sold Settled In Later Period	220,655,000	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	1,502,000	(1,038,000)	(36,000)
Swap [Member]
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Derivative, Gain (Loss) on Derivative, Net	(1,027,000)	(4,030,000)	(9,499,000)
TBA Contracts [Member]
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Derivative, Gain (Loss) on Derivative, Net	$ (4,527,000)	$ 5,938,000	$ 2,518,000