CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS, (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 7,989,000	$ 22,397,000
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Stock based compensation and equity plan amortization	453,000	492,000
Realized and unrealized (gains) losses on mortgage-backed securities	32,247,000	(10,134,000)
Derivative, Gain (Loss) on Derivative, Net	4,414,000	1,557,000
Changes in operating assets and liabilities
Accrued interest receivable	(3,898,000)	(967,000)
Other assets	(170,000)	(93,000)
Accrued interest payable	2,989,000	1,010,000
Other liabilities	(601,000)	(204,000)
Due to affiliates	196,000	15,000
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	43,619,000	14,073,000
From mortgage-backed securities investments
Purchases	(5,079,945,000)	(2,184,709,000)
Sales	3,890,959,000	1,717,612,000
Principal repayments	248,483,000	178,460,000
Proceeds From Sale Of Federal Home Loan Bank Stock	3,000	3,750,000
Payments on net settlement of to-be-announced securities	(7,945,000)	(2,145,000)
Purchase of interest rate swaptions, net of margin cash received	(410,000)	(705,000)
NET CASH USED IN INVESTING ACTIVITIES	(948,035,000)	(286,327,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from repurchase agreements	39,895,749,000	22,443,458,000
Principal payments on repurchase agreements	(38,979,377,000)	(21,944,174,000)
Principal payments on FHLB advances	0	187,500,000
Cash dividends	(47,950,000)	(28,864,000)
Proceeds From Issuance Of Common Stock, net of issuance costs	122,857,000	47,116,000
NET CASH PROVIDED BY FINANCING ACTIVITIES	991,279,000	330,036,000
NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	86,863,000	57,782,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, beginning of period	94,425,000	69,959,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, end of period	181,288,000	127,741,000
Cash paid during the period for:
Interest Paid	25,127,000	9,619,000
SUPPLEMENTAL DISCLOSURES OF NONCASH FINANCING ACTIVITIES:
Securities acquired settled in later period	0	72,343,000
Securities Sold Settled In Later Period	0	27,509,000
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	(827,000)	(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	1,398,000	(792,000)
TBA Contracts [Member]
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Derivative, Gain (Loss) on Derivative, Net	$ 3,843,000	$ 2,385,000