Consolidated Condensed Schedule of Investments (Long Investments) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) property shares	Dec. 31, 2020 USD ($) property	Dec. 31, 2019 USD ($) property
Schedule of Investments [Line Items]
Unpaid Principal Balance		$ 1,417,054	$ 1,387,733
Fair Value	$ 2,939,311
Number of Real Estate Properties | property	20	13	15
Investments, at fair value, Cost	$ 2,970,306
PercentageCollaterallizedByGNRCMOCertificates	100.00%
Non-performing loans, maturity date not applicable	$ 47,300
Mortgage Loans in Process of Foreclosure, Amount	$ 9,100
Unrated But Agency Guaranteed [Member]
Schedule of Investments [Line Items]
Long Investment Holdings Percent Of Equity by Rating	243.66%
Long Investment Aaa Rating [Member]
Schedule of Investments [Line Items]
Long Investment Holdings Percent Of Equity by Rating	0.01%
Long Investment Aa Rating [Member]
Schedule of Investments [Line Items]
Long Investment Holdings Percent Of Equity by Rating	0.63%
Long Investment Arating [Member]
Schedule of Investments [Line Items]
Long Investment Holdings Percent Of Equity by Rating	4.73%
Long Investment Bbb Rating [Member]
Schedule of Investments [Line Items]
Long Investment Holdings Percent Of Equity by Rating	1.84%
Long Investment Bb Rating [Member]
Schedule of Investments [Line Items]
Long Investment Holdings Percent Of Equity by Rating	46.34%
Long Investment Unrated Rating [Member]
Schedule of Investments [Line Items]
Long Investment Holdings Percent Of Equity by Rating	196.65%
Related Party-Consumer Loans Titled in Name of Related Party
Schedule of Investments [Line Items]
Fair value of loans held in related party trust	$ 21,900	$ 44,500	$ 47,900
Purchasing Entity
Schedule of Investments [Line Items]
Fair value of loans held in related party trust	181,500	45,100	185,400
Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 884,870
Investment Owned, Percent of Net Assets	148.68%
Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 10,510
Investment Owned, Percent of Net Assets	1.77%
To Be Announced Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance			460,037
Fair Value	$ 474,860
Investment Owned, Percent of Net Assets	79.78%
Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 1,370,240
Investment Owned, Percent of Net Assets	230.23%
Investments, at fair value, Cost	$ 1,388,115
Principal And Interest Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 60,971
Investment Owned, Percent of Net Assets	10.24%
Interest Only Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 19,006
Investment Owned, Percent of Net Assets	3.19%
Agency Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 1,450,217
Investment Owned, Percent of Net Assets	243.66%
Investments, at fair value, Cost	$ 1,469,988
Principal And Interest Private Label Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 329,317
Investment Owned, Percent of Net Assets	55.33%
Investments, at fair value, Cost	$ 326,430
Interest Only Private Label Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 7,230
Investment Owned, Percent of Net Assets	1.22%
Investments, at fair value, Cost	$ 5,189
Other Private Label Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 0
Investment Owned, Percent of Net Assets	0.00%
Investments, at fair value, Cost	$ 0
Collateralized Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 1,786,764
Investment Owned, Percent of Net Assets	300.21%
Investments, at fair value, Cost	$ 1,801,607
CLOs
Schedule of Investments [Line Items]
Fair Value	$ 123,893
Investment Owned, Percent of Net Assets	20.82%
Investments, at fair value, Cost	$ 139,424
CLOs | Related Party CLO securitization [Member]
Schedule of Investments [Line Items]
Fair Value	50,800
Consumer loans and asset-backed securities backed by consumer loans
Schedule of Investments [Line Items]
Fair Value	$ 206,761
Investment Owned, Percent of Net Assets	34.74%
Investments, at fair value, Cost	$ 211,982
Corporate debt securities
Schedule of Investments [Line Items]
Fair Value	$ 22,392
Investment Owned, Percent of Net Assets	3.76%
Investments, at fair value, Cost	$ 24,268
Secured notes
Schedule of Investments [Line Items]
Fair Value	$ 10,917
Investment Owned, Percent of Net Assets	1.83%
Investments, at fair value, Cost	$ 12,138
Mortgage Loans [Member]
Schedule of Investments [Line Items]
Fair Value	$ 708,015
Investment Owned, Percent of Net Assets	118.96%
Investments, at fair value, Cost	$ 703,366
Real estate owned
Schedule of Investments [Line Items]
Fair Value	$ 34,500
Investment Owned, Percent of Net Assets	5.80%
Investments, at fair value, Cost	$ 35,371
Common stock
Schedule of Investments [Line Items]
Fair Value	$ 2,200
Investment Owned, Percent of Net Assets	0.37%
Investments, at fair value, Cost	$ 2,482
Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 43,793
Investment Owned, Percent of Net Assets	7.36%
Investments, at fair value, Cost	$ 39,592
U.S. Treasury securities
Schedule of Investments [Line Items]
Fair Value	$ 76
Investment Owned, Percent of Net Assets	0.01%
Investments, at fair value, Cost	$ 76
Long Investments [Member]
Schedule of Investments [Line Items]
Fair Value	$ 2,939,311
Investment Owned, Percent of Net Assets	493.86%
Investments, at fair value, Cost	$ 2,970,306
Private Label Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 336,547
Investment Owned, Percent of Net Assets	56.55%
Investments, at fair value, Cost	$ 331,619
Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 79,977
Investment Owned, Percent of Net Assets	13.43%
Investments, at fair value, Cost	$ 81,873
Securitized residential mortgage loans
Schedule of Investments [Line Items]
Fair Value of Assets Transfered and Accounted for as Secured Borrowings	$ 314,200
Government National Mortgage Association [Member] | Long Investments [Member]
Schedule of Investments [Line Items]
Investment Owned, Percent of Net Assets	107.55%
Federal National Mortgage Association [Member] | Long Investments [Member]
Schedule of Investments [Line Items]
Investment Owned, Percent of Net Assets	93.99%
Federal Home Loan Mortgage Corporation [Member] | Long Investments [Member]
Schedule of Investments [Line Items]
Investment Owned, Percent of Net Assets	42.12%
Mortgage-related Commercial | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 1,100	$ 33,900	$ 17,300
North America [Member] | Principal And Interest Private Label Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 164,410
Investment Owned, Percent of Net Assets	27.62%
Investments, at fair value, Cost	$ 153,769
North America [Member] | CLOs
Schedule of Investments [Line Items]
Fair Value	$ 123,893
Investment Owned, Percent of Net Assets	20.82%
Investments, at fair value, Cost	$ 139,424
North America [Member] | Consumer loans and asset-backed securities backed by consumer loans
Schedule of Investments [Line Items]
Fair Value	$ 205,877
Investment Owned, Percent of Net Assets	34.59%
Investments, at fair value, Cost	$ 211,221
North America [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Fair Value	$ 11,586
Investment Owned, Percent of Net Assets	1.95%
Investments, at fair value, Cost	$ 11,949
North America [Member] | Common stock
Schedule of Investments [Line Items]
Fair Value	$ 2,200
Investment Owned, Percent of Net Assets	0.37%
Investments, at fair value, Cost	$ 2,482
North America [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 43,789
Investment Owned, Percent of Net Assets	7.36%
Investments, at fair value, Cost	$ 39,587
North America [Member] | Various Issuer [Member] | CLOs
Schedule of Investments [Line Items]
Unpaid Principal Balance	269,224
Fair Value	$ 123,893
North America [Member] | Various Issuer [Member] | CLOs | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	0.00%
Investments maturity date	2019-01
North America [Member] | Various Issuer [Member] | CLOs | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	10.54%
Investments maturity date	2118-10
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 143,523
Investment Interest Rate	4.00%
Fair Value	$ 147,395
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2039-09
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-11
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 111,109
Investment Interest Rate	4.00%
Fair Value	$ 114,104
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2041-11
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-12
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 82,189
Investment Interest Rate	3.50%
Fair Value	$ 82,450
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2042-09
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-02
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 74,478
Investment Interest Rate	4.50%
Fair Value	$ 77,266
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2046-09
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2049-01
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 65,892
Investment Interest Rate	4.50%
Fair Value	$ 68,853
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2041-10
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-12
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 51,362
Investment Interest Rate	4.00%
Fair Value	$ 52,544
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2045-07
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-05
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 46,026
Investment Interest Rate	5.00%
Fair Value	$ 48,245
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2048-02
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-12
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 45,670
Investment Interest Rate	4.50%
Fair Value	$ 47,583
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2043-09
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-10
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 42,663
Investment Interest Rate	3.50%
Fair Value	$ 43,241
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2028-03
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2032-03
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 38,420
Investment Interest Rate	5.00%
Fair Value	$ 40,652
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2035-10
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-08
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 32,106
Investment Interest Rate	3.50%
Fair Value	$ 32,253
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2042-12
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2047-12
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 25,082
Investment Interest Rate	3.50%
Fair Value	$ 25,185
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2042-01
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-03
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 21,807
Investment Interest Rate	5.50%
Fair Value	$ 23,207
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2048-04
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-12
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 10,899
Investment Interest Rate	3.00%
Fair Value	$ 10,895
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2030-04
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2032-09
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Fifteen Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 8,275
Investment Interest Rate	3.50%
Fair Value	$ 8,389
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Fifteen Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2028-09
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Fifteen Year) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2032-12
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Other) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 7,287
Investment Interest Rate	3.50%
Fair Value	$ 7,316
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Other) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2043-04
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Other) Three Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2046-09
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 6,096
Investment Interest Rate	5.00%
Fair Value	$ 6,423
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2044-07
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-10
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 5,728
Investment Interest Rate	4.00%
Fair Value	$ 5,823
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2026-06
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2031-05
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 5,023
Investment Interest Rate	5.50%
Fair Value	$ 5,342
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2039-11
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-06
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Other) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 4,547
Investment Interest Rate	5.00%
Fair Value	$ 4,772
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Other) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2043-09
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Other) Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2044-01
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Other) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 4,394
Investment Interest Rate	4.00%
Fair Value	$ 4,478
Investments maturity date	2047-12
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Six Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,408
Investment Interest Rate	6.00%
Fair Value	$ 3,666
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Six Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2048-05
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Six Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-11
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,773
Investment Interest Rate	3.00%
Fair Value	$ 2,722
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2043-07
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2045-06
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,603
Investment Interest Rate	3.00%
Fair Value	$ 2,556
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2042-01
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2045-06
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Three Point Seven Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,508
Investment Interest Rate	3.75%
Fair Value	$ 2,537
Investments maturity date	2047-07
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Other) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,348
Investment Interest Rate	4.50%
Fair Value	$ 2,432
Investments maturity date	2044-05
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation (15 Year) 3 Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,343
Investment Interest Rate	3.00%
Fair Value	$ 2,342
Investments maturity date	2030-04
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation (15 Year) 3 Percent [Member] | To Be Announced Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 1,660
Investment Interest Rate	3.00%
Fair Value	$ 1,655
Investments maturity date	2019-01
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Fifteen Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,177
Investment Interest Rate	4.50%
Fair Value	$ 2,265
Investments maturity date	2026-04
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Other) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,025
Investment Interest Rate	4.50%
Fair Value	$ 2,079
Investments maturity date	2041-05
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Twenty Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 1,478
Investment Interest Rate	4.00%
Fair Value	$ 1,526
Investments maturity date	2033-12
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Twenty Year) Four Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 976
Investment Interest Rate	4.50%
Fair Value	$ 1,021
Investments maturity date	2033-12
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Fifteen Year) Four Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 886
Investment Interest Rate	4.00%
Fair Value	$ 897
Investments maturity date	2029-02
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Six Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 651
Investment Interest Rate	6.00%
Fair Value	$ 697
Investments maturity date	2040-05
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Three Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 710
Investment Interest Rate	3.00%
Fair Value	$ 695
Investments maturity date	2042-11
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Six Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 588
Investment Interest Rate	6.00%
Fair Value	$ 631
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Six Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2039-09
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Six Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2040-02
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools (Thirty Year) Two Point Four Nine Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 524
Investment Interest Rate	2.49%
Fair Value	$ 496
Investments maturity date	2043-10
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools (Thirty Year) Three Point Two Eight Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 109
Investment Interest Rate	3.28%
Fair Value	$ 106
Investments maturity date	2042-06
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Four Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 17,505
Investment Interest Rate	4.00%
Fair Value	$ 2,828
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Four Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2045-02
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Four Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2045-06
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Four Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 10,446
Investment Interest Rate	4.50%
Fair Value	$ 1,223
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Four Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2020-12
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Four Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2044-06
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Six Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 4,768
Investment Interest Rate	6.00%
Fair Value	$ 978
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Six Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2038-06
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Six Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2039-08
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Four Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 5,949
Investment Interest Rate	4.50%
Fair Value	$ 808
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Four Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2039-06
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Four Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2044-07
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Five Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,401
Investment Interest Rate	5.50%
Fair Value	$ 749
Investments maturity date	2039-10
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Five Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,612
Investment Interest Rate	5.50%
Fair Value	$ 623
Investments maturity date	2043-11
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Three Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,642
Investment Interest Rate	3.50%
Fair Value	$ 515
Investments maturity date	2032-12
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Four Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,560
Investment Interest Rate	4.00%
Fair Value	$ 513
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Four Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2039-05
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Four Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2043-11
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,659
Investment Interest Rate	5.00%
Fair Value	$ 463
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2038-01
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2040-05
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 5,122
Investment Interest Rate	5.00%
Fair Value	$ 402
Investments maturity date	2038-11
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Five Point FIve Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,749
Investment Interest Rate	5.50%
Fair Value	$ 336
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Five Point FIve Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2039-01
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Five Point FIve Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2039-09
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Six Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 1,613
Investment Interest Rate	6.00%
Fair Value	$ 274
Investments maturity date	2040-01
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Four Point Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 1,463
Investment Interest Rate	4.50%
Fair Value	$ 254
Investments maturity date	2043-07
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Three Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,291
Investment Interest Rate	3.00%
Fair Value	$ 203
Investments maturity date	2041-09
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,043
Investment Interest Rate	5.00%
Fair Value	$ 181
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2037-05
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2041-05
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Four Point Seven Five Percent [Member] | Interest Only Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 842
Investment Interest Rate	4.75%
Fair Value	$ 160
Investments maturity date	2040-07
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association (30 Year) 5 Point 00 Percent [Member] | To Be Announced Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 299,455
Investment Interest Rate	5.00%
Fair Value	$ 311,515
Investments maturity date	2019-01
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association (30 Year) 4 Point 00 Percent [Member] | To Be Announced Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 122,003
Investment Interest Rate	4.00%
Fair Value	$ 124,376
Investments maturity date	2019-01
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation (30 Year) 3 Point 50 Percent [Member] | To Be Announced Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 21,540
Investment Interest Rate	3.50%
Fair Value	$ 21,529
Investments maturity date	2019-01
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association (30 Year) 5 Point 50 Percent [Member] | To Be Announced Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 10,579
Investment Interest Rate	5.50%
Fair Value	$ 11,058
Investments maturity date	2019-01
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association (30 Year) 3 Point 00 Percent [Member] | To Be Announced Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 4,800
Investment Interest Rate	3.00%
Fair Value	$ 4,727
Investments maturity date	2019-01
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 52,532
Fair Value	$ 55,475
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	4.39%
Investments maturity date	2061-07
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	4.67%
Investments maturity date	2067-12
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,515
Fair Value	$ 3,650
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	2.70%
Investments maturity date	2035-09
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	4.69%
Investments maturity date	2045-05
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 1,808
Fair Value	$ 1,846
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	3.49%
Investments maturity date	2037-06
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools [Member] | Principal And Interest Floating Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	4.72%
Investments maturity date	2044-05
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association [Member] | Interest Only Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 228,763
Fair Value	$ 10,772
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association [Member] | Interest Only Floating Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	0.38%
Investments maturity date	2031-06
North America [Member] | Mortgage-related Residential [Member] | Government National Mortgage Association [Member] | Interest Only Floating Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	5.64%
Investments maturity date	2066-10
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association [Member] | Interest Only Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 70,568
Fair Value	$ 4,880
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association [Member] | Interest Only Floating Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	1.13%
Investments maturity date	2033-06
North America [Member] | Mortgage-related Residential [Member] | Federal National Mortgage Association [Member] | Interest Only Floating Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	5.50%
Investments maturity date	2046-11
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation [Member] | Interest Only Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 48,699
Fair Value	$ 3,256
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation [Member] | Interest Only Floating Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	1.55%
Investments maturity date	2036-03
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation [Member] | Interest Only Floating Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	4.19%
Investments maturity date	2044-01
North America [Member] | Mortgage-related Residential [Member] | Resecuritization of Government National Mortgage Association [Member] | Interest Only Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 5,220
Investment Interest Rate	2.21%
Fair Value	$ 98
Investments maturity date	2060-08
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Principal And Interest Private Label Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 227,479
Fair Value	$ 149,273
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Principal And Interest Private Label Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	0.00%
Investments maturity date	2019-05
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Principal And Interest Private Label Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	24.56%
Investments maturity date	2047-03
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Interest Only Private Label Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 30,842
Fair Value	$ 3,941
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Interest Only Private Label Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	0.00%
Investments maturity date	2030-12
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Interest Only Private Label Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	2.00%
Investments maturity date	2047-09
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Other Private Label Securities [Member]
Schedule of Investments [Line Items]
Investments maturity date	2037-06
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Secured notes
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 17,608
Investment Interest Rate	5.00%
Fair Value	$ 10,917
Investments maturity date	2057-11
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Mortgage Loans [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 493,248
Fair Value	$ 496,830
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Mortgage Loans [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	2.00%
Investments maturity date	2019-03
North America [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Mortgage Loans [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	15.00%
Investments maturity date	2058-12
North America [Member] | Mortgage-related Residential [Member] | Non-Exchange Traded Preferred Equity Investment in Mortgage Originators [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 27,317
Investment Owned, Balance, Shares | shares	23
North America [Member] | Mortgage-related Residential [Member] | Non-Exchange Traded Equity Investment in Mortgage Originators [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 6,750
Investment Owned, Balance, Shares | shares	9,818
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 1,677
Investment Interest Rate	5.50%
Fair Value	$ 1,786
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2033-08
North America [Member] | Mortgage-related Residential [Member] | Federal Home Loan Mortgage Corporation Pools (Thirty Year) Five Point Five Percent [Member] | Principal And Interest Fixed Rate Agency Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2048-05
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Principal And Interest Private Label Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 37,171
Fair Value	$ 15,137
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Principal And Interest Private Label Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	2.80%
Investments maturity date	2049-03
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Principal And Interest Private Label Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	3.29%
Investments maturity date	2061-05
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Interest Only Private Label Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 41,707
Fair Value	$ 3,289
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Interest Only Private Label Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	1.25%
Investments maturity date	2049-03
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Interest Only Private Label Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	2.00%
Investments maturity date	2061-05
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Other Private Label Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 0
Investment Interest Rate	0.00%
Fair Value	$ 0
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Other Private Label Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2045-07
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Other Private Label Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2061-05
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Mortgage Loans [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 235,459
Fair Value	$ 211,185
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Mortgage Loans [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	4.31%
Investments maturity date	2019-03
North America [Member] | Mortgage-related Commercial | Various Issuer [Member] | Mortgage Loans [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	12.74%
Investments maturity date	2037-10
North America [Member] | Mortgage-related Commercial | Non-controlling Interest in Mortgage-related Private Partnership | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 1,147
North America [Member] | Consumer [Member] | Various Issuer [Member] | Consumer loans and asset-backed securities backed by consumer loans
Schedule of Investments [Line Items]
Unpaid Principal Balance	233,602
Fair Value	$ 205,877
North America [Member] | Consumer [Member] | Various Issuer [Member] | Consumer loans and asset-backed securities backed by consumer loans | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	5.31%
Investments maturity date	2019-01
North America [Member] | Consumer [Member] | Various Issuer [Member] | Consumer loans and asset-backed securities backed by consumer loans | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	76.50%
Investments maturity date	2023-12
North America [Member] | Consumer [Member] | Various Issuer [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,342
Investment Interest Rate	6.69%
Fair Value	$ 3,141
Investments maturity date	2027-01
North America [Member] | Consumer [Member] | Exchange Traded Equity [Member] | Common stock
Schedule of Investments [Line Items]
Fair Value	$ 25
Investment Owned, Balance, Shares | shares	24
North America [Member] | Consumer [Member] | Non-Exchange Traded Corporate Equity [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 0
Investment Owned, Balance, Shares | shares	1,540
North America [Member] | Consumer [Member] | Investment in unconsolidated entities | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 4,045
North America [Member] | Consumer [Member] | Non-Exchange Traded Preferred Equity Investment in Consumer Loan Originators [Member] [Domain] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 3,000
Investment Owned, Balance, Shares | shares	3,000
North America [Member] | Communications [Member] | Various Issuer [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 938
Investment Interest Rate	0.00%
Fair Value	$ 824
Investments maturity date	2022-05
North America [Member] | Communications [Member] | Non-Exchange Traded Corporate Equity [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 97
Investment Owned, Balance, Shares | shares	7
North America [Member] | Energy [Member] | Various Issuer [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 2,080
Investment Interest Rate	4.63%
Fair Value	$ 1,877
Investments maturity date	2021-09
North America [Member] | Industrial Sector [Member] | Various Issuer [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 1,755
Investment Interest Rate	3.75%
Fair Value	$ 1,742
Investments maturity date	2021-12
North America [Member] | Technology Sector [Member] | Various Issuer [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 4,570
Fair Value	$ 4,002
North America [Member] | Technology Sector [Member] | Various Issuer [Member] | Corporate debt securities | Minimum
Schedule of Investments [Line Items]
Investments maturity date	2020-05
North America [Member] | Technology Sector [Member] | Various Issuer [Member] | Corporate debt securities | Maximum
Schedule of Investments [Line Items]
Investments maturity date	2022-05
North America [Member] | Financial [Member] | Exchange Traded Equity [Member] | Common stock
Schedule of Investments [Line Items]
Fair Value	$ 2,175
Investment Owned, Balance, Shares | shares	213
North America [Member] | Real estate-related [Member] | Single-Family Houses [Member] | Real estate owned
Schedule of Investments [Line Items]
Fair Value	$ 1,296
Number of Real Estate Properties | property	5
North America [Member] | Real estate-related [Member] | Commercial Property [Member] | Real estate owned
Schedule of Investments [Line Items]
Fair Value	$ 33,204
Number of Real Estate Properties | property	18
North America [Member] | Diversified [Member] | Non-Exchange Traded Corporate Equity [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 1,433
Investment Owned, Balance, Shares | shares	144
North America [Member] | Government Sector [Member] | U.S. Treasury Note, 2.75 Percent, Maturity Date 2023 04 [Member] | U.S. Treasury securities
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 75
Investment Interest Rate	2.75%
Fair Value	$ 76
Investments maturity date	2023-04
Europe [Member] | Principal And Interest Private Label Securities [Member]
Schedule of Investments [Line Items]
Fair Value	$ 164,907
Investment Owned, Percent of Net Assets	27.71%
Investments, at fair value, Cost	$ 172,661
Europe [Member] | Consumer loans and asset-backed securities backed by consumer loans
Schedule of Investments [Line Items]
Fair Value	$ 884
Investment Owned, Percent of Net Assets	0.15%
Investments, at fair value, Cost	$ 761
Europe [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Fair Value	$ 10,806
Investment Owned, Percent of Net Assets	1.81%
Investments, at fair value, Cost	$ 12,319
Europe [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 4
Investment Owned, Percent of Net Assets	0.00%
Investments, at fair value, Cost	$ 5
Europe [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Principal And Interest Private Label Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	183,154
Fair Value	$ 149,425
Europe [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Principal And Interest Private Label Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	0.00%
Investments maturity date	2025-06
Europe [Member] | Mortgage-related Residential [Member] | Various Issuer [Member] | Principal And Interest Private Label Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	5.50%
Investments maturity date	2052-12
Europe [Member] | Mortgage-related Commercial | Various Issuer [Member] | Principal And Interest Private Label Securities [Member]
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 24,978
Fair Value	$ 15,482
Europe [Member] | Mortgage-related Commercial | Various Issuer [Member] | Principal And Interest Private Label Securities [Member] | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	0.38%
Investments maturity date	2020-10
Europe [Member] | Mortgage-related Commercial | Various Issuer [Member] | Principal And Interest Private Label Securities [Member] | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	4.29%
Investments maturity date	2045-08
Europe [Member] | Consumer [Member] | Various Issuer [Member] | Consumer loans and asset-backed securities backed by consumer loans
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 3,540
Investment Interest Rate	0.00%
Fair Value	$ 884
Investments maturity date	2030-12
Europe [Member] | Consumer [Member] | Various Issuer [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 20,574
Investment Interest Rate	0.00%
Fair Value	$ 0
Investments maturity date	2019-12
Europe [Member] | Consumer [Member] | Non-Exchange Traded Corporate Equity [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 0
Investment Owned, Balance, Shares | shares	125
Europe [Member] | Technology Sector [Member] | Various Issuer [Member] | Corporate debt securities | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	0.00%
Europe [Member] | Technology Sector [Member] | Various Issuer [Member] | Corporate debt securities | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	4.38%
Europe [Member] | Financial [Member] | Various Issuer [Member] | Corporate debt securities
Schedule of Investments [Line Items]
Unpaid Principal Balance	$ 11,235
Fair Value	$ 10,806
Europe [Member] | Financial [Member] | Various Issuer [Member] | Corporate debt securities | Minimum
Schedule of Investments [Line Items]
Investment Interest Rate	0.00%
Investments maturity date	2020-10
Europe [Member] | Financial [Member] | Various Issuer [Member] | Corporate debt securities | Maximum
Schedule of Investments [Line Items]
Investment Interest Rate	16.00%
Investments maturity date	2022-11
Europe [Member] | Financial [Member] | Non-Exchange Traded Corporate Equity [Member] | Corporate equity securities
Schedule of Investments [Line Items]
Fair Value	$ 4
Investment Owned, Balance, Shares | shares	0