CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS, (Unaudited)	3 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ (16,377,000)	$ 2,449,000
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Stock based compensation and equity plan amortization	80,000	243,000
Realized and unrealized (gains) losses on mortgage-backed securities	80,050,000	16,308,000
Derivative, Gain (Loss) on Derivative, Net	(21,700,000)	(1,534,000)
Changes in operating assets and liabilities
Accrued interest receivable	(1,105,000)	(1,676,000)
Other assets	(251,000)	(417,000)
Accrued interest payable	636,000	164,000
Other liabilities	218,000	1,819,000
Due to affiliates	(1,000)	262,000
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	41,550,000	17,618,000
From mortgage-backed securities investments
Purchases	(517,829,000)	(1,737,240,000)
Sales	228,691,000	1,407,673,000
Principal repayments	78,720,000	73,298,000
Proceeds From Sale Of Federal Home Loan Bank Stock	0	3,000
Payments on net settlement of to-be-announced securities	9,161,000	1,119,000
Purchase of interest rate swaptions, net of margin cash received	(10,622,000)	0
NET CASH USED IN INVESTING ACTIVITIES	(190,635,000)	(255,147,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from repurchase agreements	13,098,449,000	11,947,907,000
Principal payments on repurchase agreements	(13,012,955,000)	(11,691,004,000)
Cash dividends	(19,116,000)	(13,869,000)
Proceeds From Issuance Of Common Stock, net of issuance costs	0	12,793,000
NET CASH PROVIDED BY FINANCING ACTIVITIES	66,378,000	255,827,000
NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(82,707,000)	18,298,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, beginning of period	246,712,000	94,425,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, end of period	164,005,000	112,723,000
Cash paid during the period for:
Interest Paid	14,513,000	6,551,000
SUPPLEMENTAL DISCLOSURES OF NONCASH FINANCING ACTIVITIES:
Securities acquired settled in later period	32,054,000	0
Securities Sold Settled In Later Period	159,300,000	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	(1,717,000)	0
Swap [Member]
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Derivative, Gain (Loss) on Derivative, Net	(11,576,000)	(1,534,000)
TBA Contracts [Member]
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Derivative, Gain (Loss) on Derivative, Net	$ (8,407,000)	$ 0