Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ 4,706,961		$ (7,989,955)		$ 450,479
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Other-than-temporary impairment charges	0		725,132		3,636,431
Amortization/accretion of available-for-sale securities premiums and discounts, net	(1,475,701)		(6,751,667)		(13,210,849)
Realized (gain) loss on sale of investments, net	14,054,164		7,216,137		533,832
Realized (gain) loss on derivative contracts, net	(2,219,719)		3,089,001		12,024,730
Realized (gain) loss on mortgage loans held-for-sale	221,620		(94,187)		(1,216,314)
Unrealized (gain) loss on fair value option securities	(9,448,270)		4,683,410		1,041,649
Unrealized (gain) loss on derivative contracts	2,704,413		(5,495,463)		(4,909,858)
Unrealized (gain) loss on mortgage loans held-for-sale	(17,727)		151,023		197,179
Unrealized (gain) loss on mortgage servicing rights	487,856		827,864		671,957
Unrealized (gain) loss on multi-family loans held in securitization trusts	(3,353,365)		5,219,530		(6,097,000)
Unrealized (gain) loss on residential loans held in securitization trusts	961,100		(404,720)		8,153,474
Restricted stock compensation expense	(6,280)		35,785		63,275
Net change in:
Accrued interest receivable	(1,547,501)		(707,019)		1,204,188
Deferred offering costs	(82,893)		(96,489)		945,661
Other assets	118,914		(218,541)		(484,891)
Accrued interest payable	1,028,149		119,993		(693,848)
Deferred income	18,775		203,743		0
Fees and expenses payable to Manager	(128,000)		37,097		(219,097)
Other accounts payable and accrued expenses	(1,784,642)		1,790,336		(27,522)
Net cash provided by operating activities	4,237,854		2,341,010		2,063,476
Cash flows from investing activities:
Purchase of available-for-sale securities	(1,060,558,013)		(585,984,081)		(241,590,864)
Purchase of mortgage loans held-for-sale	0		(14,772,535)		(502,308,627)
Purchase of mortgage servicing rights	(10,910)		0		(4,940,630)
Purchase of FHLBI stock	0		0		(2,403,000)
Proceeds from sales of available-for-sale securities	495,030,356		263,153,843		333,672,932
Proceeds from mortgage loans held-for-sale	2,098,010		22,490,929		531,673,280
Proceeds from FHLBI stock	0		2,403,000		0
Net proceeds from (payments for) derivative contracts	2,219,506		(3,089,001)		(11,940,730)
Principal payments from available-for-sale securities	136,715,868		96,655,967		70,476,212
Principal payments from mortgage loans held-for-sale	547,635		275,636		15,432,462
Investment related receivable	(3,546,670)		(2,323,115)		0
Due to broker	(3,121,215)		4,244,678		0
Net cash (used in) provided by investing activities	(430,625,433)		(216,944,679)		188,071,035
Cash flows from financing activities:
Proceeds from issuance of common stock	19,835,626		15,503,885		0
Purchase of treasury stock	0		(283,565)		(358,991)
Dividends paid on common stock	(11,904,005)		(29,898,918)		(19,874,663)
Dividends paid on preferred stock	(3,522,036)		(3,522,036)		(3,522,036)
Proceeds from repurchase agreements - available-for-sale securities	14,224,216,000		7,940,492,000		5,951,792,999
Proceeds from repurchase agreements - mortgage loans held-for-sale	0		16,405,081		66,937,322
Proceeds from FHLBI advances	0		0		155,497,000
Payments for FHLBI advances	0		(49,697,000)		(105,800,000)
Principal repayments of repurchase agreements - available-for-sale securities	(13,794,505,000)		(7,644,912,000)		(6,136,468,999)
Principal repayments of repurchase agreements - mortgage loans held-for-sale	0		(25,909,538)		(107,696,717)
Net cash (used in) provided by financing activities	434,120,585		218,177,909		(199,494,085)
Net increase (decrease) in cash, cash equivalents and restricted cash	7,733,006		3,574,240		(9,359,574)
Cash, cash equivalents and restricted cash, beginning of period	37,889,596		34,315,356		43,674,930
Cash, cash equivalents and restricted cash, end of period	45,622,602		37,889,596		34,315,356
Supplemental disclosure of cash flow information
Cash paid for interest	14,477,370		6,355,591		8,554,565
Non-cash investing and financing activities information
Dividends declared but not paid at end of period	39,132	[1]	39,132	[1]	39,132
Net change in unrealized gain (loss) on available-for-sale securities	(5,785,854)		(8,872,859)		(7,604,122)
Consolidation of multi-family loans held in securitization trusts	1,135,251,880		1,227,523,075		1,455,155,339
Consolidation of residential loans held in securitization trusts	120,152,455		141,597,866		413,327,217
Consolidation of multi-family securitized debt obligations	1,113,556,782		1,209,181,035		1,369,124,789
Consolidation of residential securitized debt obligations	114,738,735		135,223,045		381,791,476
MBS securities recorded upon adoption of revised accounting standard for repurchase agreement financing	0		0		210,238,658
Repurchase agreements recorded upon adoption of revised accounting standard for repurchase agreement financing	$ 0		$ 0		$ 149,293,000

[1] Our consolidated balance sheets include assets and liabilities of consolidated variable interest entities (“VIE's) as the Company is the primary beneficiary of these VIEs. As of December 31, 2017 and December 31, 2016, assets of consolidated VIEs totaled $1,255,404,335 and $1,369,120,941, respectively, and the liabilities of consolidated VIEs totaled $1,228,295,517 and $1,344,404,080, respectively