AVAILABLE-FOR-SALE SECURITIES - Components of Interest Income on AFS Securities (Details) - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Coupon interest	$ 8,323,342	$ 5,422,834
Net (premium amortization)/ discount accretion	(1,243,752)	1,399,788
Interest income	7,079,590	6,822,622
Agency
Schedule of Available-for-sale Securities [Line Items]
Coupon interest	8,323,342	5,380,580
Net (premium amortization)/ discount accretion	(1,275,855)	466,291
Interest income	7,047,487	5,846,871
Non-Agency
Schedule of Available-for-sale Securities [Line Items]
Coupon interest	0	42,254
Net (premium amortization)/ discount accretion	0	9,946
Interest income	0	52,200
Multi-Family
Schedule of Available-for-sale Securities [Line Items]
Coupon interest	0	0
Net (premium amortization)/ discount accretion	32,103	923,551
Interest income	$ 32,103	$ 923,551

Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

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Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(a),(b))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.9)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Amount of accretion (amortization) of purchase discount (premium) on nonoperating securities.

+ References

+ Details

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+ References

No definition available.

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