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Mortgage-Backed Securities Interest Income Components (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest Income Components [Line Items]
Net Amortization	$ (4,219)	$ (701)
Interest income	13,426	12,329
Agency RMBS [Member]
Interest Income Components [Line Items]
Coupon Interest	16,908	12,579
Net Amortization	(4,248)	(755)
Interest income	12,660	11,824
Non-Agency RMBS [Member]
Interest Income Components [Line Items]
Coupon Interest	169	253
Net Amortization	86	101
Interest income	255	354
Residential Mortgage Backed Securities [Member]
Interest Income Components [Line Items]
Coupon Interest	17,077	12,832
Net Amortization	(4,162)	(654)
Interest income	$ 12,915	$ 12,178

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- Definition

[Line Items] for Interest Income Components [Table]

+ References

No definition available.

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- Definition

The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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- Definition

Amount of the required periodic payments applied to interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount of operating interest income, including, but not limited to, amortization and accretion of premiums and discounts on 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 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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