Consolidated Condensed Schedule Of Investments (Long Investments) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013		Dec. 31, 2012
Schedule of Investments [Line Items]
Fair Value	$ 1,535,924		$ 1,375,116
Investment Owned, at Cost	1,465,788		1,328,153
Percentage collaterallized by GNRCMO certificates	100.00%		100.00%
Unrated But Agency-Guaranteed [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	182.67%		161.52%
Long Investment AAA Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	0.01%		0.01%
Long Investment AA Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	0.00%		0.26%
Long Investment A Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	1.29%		1.02%
Long Investment BBB Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	2.41%		3.70%
Long Investment BB Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	104.70%		102.40%
Long Investment Unrated Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	3.95%		2.66%
Principal And Interest - Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	159.48%	[1],[2],[3],[4]	148.21%	[1],[2],[5],[6]
Fair Value	830,266	[1],[3],[4]	750,454	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 49,189 Federal National Mortgage Association Pool 3.50% 2042-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	49,189	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-12	[1],[3],[4]
Fair Value	52,092	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 45,060 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	45,060	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	47,650	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 39,792 Federal National Mortgage Association Pool 3.50% 2043-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	39,792	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2043-01	[1],[3],[4]
Fair Value	42,279	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 20,398 Federal National Mortgage Association Pool 4.50% 2041-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	20,398	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-12	[1],[3],[4]
Fair Value	22,178	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,762 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	17,762	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-09	[1],[3],[4]
Fair Value	19,313	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,949 Federal National Mortgage Association Pool 3.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	17,949	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-08	[1],[3],[4]
Fair Value	19,076	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,069 Federal National Mortgage Association Pool 5.00% 2041-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	17,069	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2041-08	[1],[3],[4]
Fair Value	18,599	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 16,771 Federal National Mortgage Association Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	16,771	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-10	[1],[3],[4]
Fair Value	18,235	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 16,051 Federal Home Loan Mortgage Corporation Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	16,051	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2041-07	[1],[3],[4]
Fair Value	17,470	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 14,612 Federal National Mortgage Association Pool 5.00% 2041-03 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	14,612	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2041-03	[1],[3],[4]
Fair Value	16,050	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 14,033 Federal National Mortgage Association Pool 3.50% 2043-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	14,033	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2043-04	[1],[3],[4]
Fair Value	14,820	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 13,478 Federal National Mortgage Association Pool 4.00% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	13,478	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-08	[1],[3],[4]
Fair Value	14,499	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 13,431 Federal National Mortgage Association Pool 3.50% 2043-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	13,431	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2043-04	[1],[3],[4]
Fair Value	14,218	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 13,268 Federal Home Loan Mortgage Corporation Pool 3.00% 2042-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	13,268	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.00%	[1],[3],[4]
Maturity	2042-10	[1],[3],[4]
Fair Value	13,646	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 11,483 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	11,483	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-09	[1],[3],[4]
Fair Value	12,414	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 11,470 Federal National Mortgage Association Pool 4.00% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	11,470	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2041-11	[1],[3],[4]
Fair Value	12,271	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 10,960 Federal National Mortgage Association Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	10,960	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2041-07	[1],[3],[4]
Fair Value	12,011	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 10,122 Federal National Mortgage Association Pool 4.00% 2042-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	10,122	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-01	[1],[3],[4]
Fair Value	10,807	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 10,098 Federal Home Loan Mortgage Corporation Pool 3.00% 2043-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	10,098	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.00%	[1],[3],[4]
Maturity	2043-02	[1],[3],[4]
Fair Value	10,384	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,090 Federal National Mortgage Association Pool 4.50% 2026-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	9,090	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2026-04	[1],[3],[4]
Fair Value	9,808	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 8,963 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	8,963	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-10	[1],[3],[4]
Fair Value	9,705	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 8,048 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	8,048	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-02	[1],[3],[4]
Fair Value	8,720	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 7,049 Federal National Mortgage Association Pool 5.50% 2039-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	7,049	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.50%	[1],[3],[4]
Maturity	2039-10	[1],[3],[4]
Fair Value	7,728	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 6,300 Federal National Mortgage Association Pool 4.00% 2026-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	6,300	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2026-07	[1],[3],[4]
Fair Value	6,745	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 6,296 Federal National Mortgage Association Pool 3.50% 2043-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	6,296	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2043-02	[1],[3],[4]
Fair Value	6,656	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,581 Government National Mortgage Association 4.54% 2062-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,581	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.54%	[1],[3],[4]
Maturity	2062-11	[1],[3],[4]
Fair Value	6,378	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,482 Government National Mortgage Association 4.46% 2063-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,482	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.46%	[1],[3],[4]
Maturity	2063-02	[1],[3],[4]
Fair Value	6,272	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,897 Federal National Mortgage Association Pool 3.50% 2042-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,897	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-05	[1],[3],[4]
Fair Value	6,249	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,339 Government National Mortgage Association 4.52% 2063-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,339	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.52%	[1],[3],[4]
Maturity	2063-01	[1],[3],[4]
Fair Value	6,111	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,329 Government National Mortgage Association 4.58% 2062-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,329	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.58%	[1],[3],[4]
Maturity	2062-10	[1],[3],[4]
Fair Value	6,085	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,562 Federal National Mortgage Association Pool 4.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,562	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2041-10	[1],[3],[4]
Fair Value	6,014	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,452 Federal National Mortgage Association Pool 5.00% 2041-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,452	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2041-06	[1],[3],[4]
Fair Value	5,941	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,143 Government National Mortgage Association 4.60% 2062-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,143	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.60%	[1],[3],[4]
Maturity	2062-06	[1],[3],[4]
Fair Value	5,850	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,186 Government National Mortgage Association 4.63% 2061-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,186	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.63%	[1],[3],[4]
Maturity	2061-06	[1],[3],[4]
Fair Value	5,828	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,385 Federal National Mortgage Association Pool 3.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,385	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-08	[1],[3],[4]
Fair Value	5,690	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,275 Federal Home Loan Mortgage Corporation Pool 4.00% 2042-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,275	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-05	[1],[3],[4]
Fair Value	5,670	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,333 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,333	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	5,638	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,061 Federal National Mortgage Association Pool 4.00% 2042-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,061	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-04	[1],[3],[4]
Fair Value	5,475	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,021 Federal National Mortgage Association Pool 5.00% 2040-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,021	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2040-11	[1],[3],[4]
Fair Value	5,471	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,005 Federal National Mortgage Association Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,005	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2041-07	[1],[3],[4]
Fair Value	5,422	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,677 Federal National Mortgage Association Pool 4.50% 2041-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,677	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-08	[1],[3],[4]
Fair Value	5,056	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,587 Federal National Mortgage Association Pool 5.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,587	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2041-10	[1],[3],[4]
Fair Value	4,992	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,701 Federal National Mortgage Association Pool 3.50% 2042-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,701	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-07	[1],[3],[4]
Fair Value	4,966	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,624 Federal National Mortgage Association Pool 3.50% 2043-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,624	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2043-04	[1],[3],[4]
Fair Value	4,896	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,487 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,487	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	4,761	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,496 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,496	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-09	[1],[3],[4]
Fair Value	4,755	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,442 Federal Home Loan Mortgage Corporation Pool 4.00% 2042-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,442	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-02	[1],[3],[4]
Fair Value	4,741	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,359 Federal National Mortgage Association Pool 4.00% 2042-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,359	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-09	[1],[3],[4]
Fair Value	4,689	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,335 Federal National Mortgage Association Pool 4.00% 2026-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,335	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2026-06	[1],[3],[4]
Fair Value	4,642	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,236 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,236	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	4,486	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,144 Federal National Mortgage Association Pool 3.00% 2027-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,144	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.00%	[1],[3],[4]
Maturity	2027-07	[1],[3],[4]
Fair Value	4,364	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,906 Federal National Mortgage Association Pool 3.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,906	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-08	[1],[3],[4]
Fair Value	4,126	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,848 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,848	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-10	[1],[3],[4]
Fair Value	4,057	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,651 Federal National Mortgage Association Pool 5.00% 2035-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,651	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2035-10	[1],[3],[4]
Fair Value	4,011	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,767 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,767	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	3,977	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,413 Government National Mortgage Assocation 4.66% 2063-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,413	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.66%	[1],[3],[4]
Maturity	2063-01	[1],[3],[4]
Fair Value	3,935	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,590 Federal National Mortgage Association Pool 4.50% 2042-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,590	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2042-04	[1],[3],[4]
Fair Value	3,913	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,300 Government National Mortgage Association 4.48% 2063-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,300	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.48%	[1],[3],[4]
Maturity	2063-02	[1],[3],[4]
Fair Value	3,798	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,341 Government National Mortgage Association 4.80% 2061-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,341	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.80%	[1],[3],[4]
Maturity	2061-02	[1],[3],[4]
Fair Value	3,742	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,551 Federal National Mortgage Association Pool 3.00% 2027-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,551	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.00%	[1],[3],[4]
Maturity	2027-08	[1],[3],[4]
Fair Value	3,739	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,478 Federal National Mortgage Association Pool 3.50% 2027-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,478	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2027-06	[1],[3],[4]
Fair Value	3,714	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,513 Federal National Mortgage Association Pool 3.50% 2042-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,513	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-12	[1],[3],[4]
Fair Value	3,714	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,403 Federal National Mortgage Association Pool 4.00% 2042-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,403	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-04	[1],[3],[4]
Fair Value	3,668	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,464 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,464	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	3,650	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,392 Federal Home Loan Mortgage Corporation Pool 4.00% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,392	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2041-11	[1],[3],[4]
Fair Value	3,624	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,378 Federal Home Loan Mortgage Corporation Pool 4.00% 2042-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,378	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-01	[1],[3],[4]
Fair Value	3,609	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,147 Government National Mortgage Association 4.68% 2061-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,147	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.68%	[1],[3],[4]
Maturity	2061-10	[1],[3],[4]
Fair Value	3,557	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,244 Federal National Mortgage Association Pool 5.00% 2040-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,244	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.00%	[1],[3],[4]
Maturity	2040-06	[1],[3],[4]
Fair Value	3,535	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,256 Federal National Mortgage Association Pool 4.00% 2042-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,256	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-09	[1],[3],[4]
Fair Value	3,503	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,399 Federal Home Loan Mortgage Corporation Pool 3.00% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,399	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.00%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	3,497	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,184 Federal National Mortgage Association Pool 4.50% 2041-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,184	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-12	[1],[3],[4]
Fair Value	3,442	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,167 Federal National Mortgage Association Pool 4.00% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,167	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-08	[1],[3],[4]
Fair Value	3,405	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,196 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,196	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-02	[1],[3],[4]
Fair Value	3,385	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,046 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,046	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-09	[1],[3],[4]
Fair Value	3,298	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,952 Federal Home Loan Mortgage Corporation Pool 6.00% 2039-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,952	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	6.00%	[1],[3],[4]
Maturity	2039-04	[1],[3],[4]
Fair Value	3,226	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,039 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,039	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	3,213	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,919 Federal National Mortgage Association Pool 4.00% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,919	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-08	[1],[3],[4]
Fair Value	3,147	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,738 Government National Mortgage Association 4.49% 2062-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,738	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.49%	[1],[3],[4]
Maturity	2062-11	[1],[3],[4]
Fair Value	3,125	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,905 Federal National Mortgage Association Pool 3.50% 2027-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,905	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2027-07	[1],[3],[4]
Fair Value	3,096	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,815 Federal National Mortgage Association Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,815	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-10	[1],[3],[4]
Fair Value	3,053	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,629 Government National Mortgage Association 4.58% 2062-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,629	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.58%	[1],[3],[4]
Maturity	2062-11	[1],[3],[4]
Fair Value	3,009	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,610 Government National Mortgage Association 4.55% 2062-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,610	[1],[3],[4]
Description	Government National Mortgage Association	[1],[3],[4]
Rate	4.55%	[1],[3],[4]
Maturity	2062-10	[1],[3],[4]
Fair Value	2,983	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,677 Federal National Mortgage Association Pool 4.50% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,677	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.50%	[1],[3],[4]
Maturity	2041-11	[1],[3],[4]
Fair Value	2,893	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,623 Federal National Mortgage Association Pool 4.00% 2043-03 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,623	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2043-03	[1],[3],[4]
Fair Value	2,822	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,555 Federal National Mortgage Association Pool 4.00% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,555	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-08	[1],[3],[4]
Fair Value	2,747	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,485 Federal National Mortgage Association Pool 4.00% 2042-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,485	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2042-09	[1],[3],[4]
Fair Value	2,672	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,507 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,507	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	2,650	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,486 Federal National Mortgage Association Pool 3.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,486	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-08	[1],[3],[4]
Fair Value	2,644	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,505 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,505	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Fair Value	2,640	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,488 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,488	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2042-01	[1],[3],[4]
Fair Value	2,626	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,925 Other Government National Mortgage Association Pools [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,925	[1],[3],[4]
Description	Other Government National Mortgage Association Pools	[1],[3],[4]
Fair Value	3,309	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,925 Other Government National Mortgage Association Pools [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	4.68%	[1],[3],[4]
Maturity	2061-12	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,925 Other Government National Mortgage Association Pools [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	4.65%	[1],[3],[4]
Maturity	2061-11	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	83,131	[1],[3],[4]	69,330	[1],[5],[6]
Description	Other Federal National Mortgage Association Pools	[1],[3],[4]	Other Federal National Mortgage Association Pools	[1],[5],[6]
Fair Value	89,028	[1],[3],[4]	74,508	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	6.00%	[1],[3],[4]	6.00%	[1],[5],[6]
Maturity	2043-04	[1],[3],[4]	2043-01	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	3.00%	[1],[3],[4]	2.50%	[1],[5],[6]
Maturity	2026-03	[1],[3],[4]	2026-03	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 49,427 Federal National Mortgage Association Pool, 3.50% 2042-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			49,427	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-12	[1],[5],[6]
Fair Value			52,864	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 45,304 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			45,304	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			48,596	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 35,601 Federal National Mortgage Association Pool 5.00% 2037-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			35,601	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2037-07	[1],[5],[6]
Fair Value			38,657	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 21,338 Federal National Mortgage Association Pool 4.50% 2041-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			21,338	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-12	[1],[5],[6]
Fair Value			23,268	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 18,227 Federal National Mortgage Association Pool 3.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			18,227	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			19,552	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,845 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			17,845	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-09	[1],[5],[6]
Fair Value			19,459	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,634 Federal Home Loan Mortgage Corporation Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			17,634	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2041-07	[1],[5],[6]
Fair Value			19,218	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,621 Federal National Mortgage Association Pool 5.00% 2041-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			17,621	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2041-08	[1],[5],[6]
Fair Value			19,201	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,113 Federal National Mortgage Association Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			17,113	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-10	[1],[5],[6]
Fair Value			18,661	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 15,869 Federal National Mortgage Association Pool 5.00% 2041-03 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			15,869	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2041-03	[1],[5],[6]
Fair Value			17,430	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 14,911 Federal National Mortgage Association Pool 3.00% 2042-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			14,911	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.00%	[1],[5],[6]
Maturity			2042-10	[1],[5],[6]
Fair Value			15,642	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 14,242 Federal National Mortgage Association Pool 4.00% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			14,242	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			15,407	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 13,519 Federal Home Loan Mortgage Corporation Pool 3.00% 2042-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			13,519	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.00%	[1],[5],[6]
Maturity			2042-10	[1],[5],[6]
Fair Value			14,157	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 11,985 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			11,985	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-09	[1],[5],[6]
Fair Value			12,994	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 11,942 Federal National Mortgage Association Pool 4.00% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			11,942	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2041-11	[1],[5],[6]
Fair Value			12,848	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 11,003 Federal National Mortgage Association Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			11,003	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2041-07	[1],[5],[6]
Fair Value			12,058	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 10,576 Federal National Mortgage Association Pool 4.00% 2042-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			10,576	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-01	[1],[5],[6]
Fair Value			11,355	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,576 Federal National Mortgage Association Pool 4.50% 2026-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,576	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2026-04	[1],[5],[6]
Fair Value			10,338	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,002 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,002	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-10	[1],[5],[6]
Fair Value			9,772	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 8,321 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			8,321	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-02	[1],[5],[6]
Fair Value			9,038	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 7,395 Federal National Mortgage Association Pool 5.50% 2039-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			7,395	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.50%	[1],[5],[6]
Maturity			2039-10	[1],[5],[6]
Fair Value			8,075	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 7,428 Eight Federal National Mortgage Association Pool 3.50% 2042-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			7,428	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-10	[1],[5],[6]
Fair Value			7,984	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 7,352 Federal National Mortgage Association Pool 4.00% 2026-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			7,352	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2026-07	[1],[5],[6]
Fair Value			7,888	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 6,324 Federal National Mortgage Association Pool 5.00% 2041-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,324	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2041-06	[1],[5],[6]
Fair Value			6,891	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,929 Federal National Mortgage Association Pool 3.50% 2042-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,929	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-05	[1],[5],[6]
Fair Value			6,356	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,689 Federal Home Loan Mortgage Corporation Pool 4.00% 2042-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,689	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-05	[1],[5],[6]
Fair Value			6,141	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,592 Federal National Mortgage Association Pool 4.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,592	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2041-10	[1],[5],[6]
Fair Value			6,079	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,642 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,642	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			6,020	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,494 Federal National Association Pool 3.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,494	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			5,862	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,085 Federal National Mortgage Association Pool 5.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,085	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2041-10	[1],[5],[6]
Fair Value			5,534	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,085 Federal National Mortgage Association Pool 4.00% 2042-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,085	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-04	[1],[5],[6]
Fair Value			5,531	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,045 Federal National Mortgage Association Pool 5.00% 2040-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,045	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2040-11	[1],[5],[6]
Fair Value			5,497	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,025 Federal National Mortgage Association Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,025	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2041-07	[1],[5],[6]
Fair Value			5,444	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,944 Federal National Mortgage Association Pool 4.50% 2041-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,944	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-08	[1],[5],[6]
Fair Value			5,361	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,911 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,911	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-09	[1],[5],[6]
Fair Value			5,242	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,676 Federal National Mortgage Association Pool 4.00% 2042-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,676	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-09	[1],[5],[6]
Fair Value			5,059	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,725 Federal National Mortgage Association Pool 3.50% 2042-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,725	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-07	[1],[5],[6]
Fair Value			5,042	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,699 Federal National Mortgage Association Pool 4.00% 2026-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,699	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2026-06	[1],[5],[6]
Fair Value			5,041	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,513 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,513	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			4,828	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,465 Federal Home Loan Mortgage Corporation Pool 4.00% 2042-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,465	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-02	[1],[5],[6]
Fair Value			4,787	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,456 Federal National Mortgage Association Pool 3.00% 2027-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,456	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.00%	[1],[5],[6]
Maturity			2027-07	[1],[5],[6]
Fair Value			4,710	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,261 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,261	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			4,573	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,009 Federal Home Loan Mortgage Corporation Pool 4.00% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,009	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2041-11	[1],[5],[6]
Fair Value			4,303	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,964 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,964	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			4,229	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,926 Federal National Mortgage Association Pool 3.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,926	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			4,189	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,798 Federal National Mortgage Association Pool 5.00% 2035-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,798	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2035-10	[1],[5],[6]
Fair Value			4,172	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,864 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,864	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-10	[1],[5],[6]
Fair Value			4,116	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,728 Federal National Mortgage Association Pool 5.00% 2040-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,728	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.00%	[1],[5],[6]
Maturity			2040-06	[1],[5],[6]
Fair Value			4,062	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,726 Federal National Mortgage Association Pool 4.50% 2041-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,726	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-12	[1],[5],[6]
Fair Value			4,040	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,763 Federal National Mortgage Association Pool 3.50% 2027-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,763	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2027-06	[1],[5],[6]
Fair Value			4,022	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,766 Federal National Mortgage Association Pool 3.00% 2027-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,766	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.00%	[1],[5],[6]
Maturity			2027-08	[1],[5],[6]
Fair Value			3,980	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,606 Federal National Mortgage Association Pool 4.50% 2042-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,606	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2042-04	[1],[5],[6]
Fair Value			3,941	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,526 Federal Home Loan Mortgage Corporation Pool 6.00% 2039-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,526	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			6.00%	[1],[5],[6]
Maturity			2039-04	[1],[5],[6]
Fair Value			3,848	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,534 Federal National Mortgage Association Pool 3.50% 2042-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,534	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-12	[1],[5],[6]
Fair Value			3,770	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,442 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,442	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-09	[1],[5],[6]
Fair Value			3,737	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,483 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,483	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			3,712	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,419 Federal National Mortgage Association Pool 4.00% 2042-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,419	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-04	[1],[5],[6]
Fair Value			3,706	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,404 Federal Home Loan Mortgage Corporation Pool 4.00% 2042-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,404	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-01	[1],[5],[6]
Fair Value			3,653	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,344 Federal National Mortgage Association Pool 4.00% 2042-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,344	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-09	[1],[5],[6]
Fair Value			3,618	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,415 Federal Home Loan Mortgage Corporation Pool 3.00% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,415	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.00%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			3,573	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,288 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,288	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-02	[1],[5],[6]
Fair Value			3,518	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,182 Federal National Mortgage Association Pool 4.00% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,182	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			3,440	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,095 Federal National Mortgage Association Pool 4.50% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,095	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-11	[1],[5],[6]
Fair Value			3,355	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,053 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,053	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			3,262	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,931 Federal National Mortgage Association Pool 4.00% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,931	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			3,178	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,947 Federal National Mortgage Association Pool 3.50% 2027-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,947	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2027-07	[1],[5],[6]
Fair Value			3,145	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,921 Federal National Mortgage Association Pool 3.50% 2027-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,921	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2027-06	[1],[5],[6]
Fair Value			3,123	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,828 Federal National Mortgage Association Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,828	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-10	[1],[5],[6]
Fair Value			3,076	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,605 Government National Mortgage Association 4.55% 2062-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,605	[1],[5],[6]
Description			Government National Mortgage Association	[1],[5],[6]
Rate			4.55%	[1],[5],[6]
Maturity			2062-10	[1],[5],[6]
Fair Value			2,977	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,676 Federal National Mortgage Association Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,676	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2041-10	[1],[5],[6]
Fair Value			2,901	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,566 Federal National Mortgage Association Pool 4.00% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,566	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			2,774	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,490 Federal National Mortgage Association Pool 4.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,490	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.50%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			2,719	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,497 Federal National Mortgage Association Pool 4.00% 2042-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,497	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-09	[1],[5],[6]
Fair Value			2,699	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,519 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,519	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			2,690	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,520 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,520	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			2,685	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,498 Federal National Mortgage Association Pool 3.50% 2042-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,498	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-08	[1],[5],[6]
Fair Value			2,679	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,500 Federal Home Loan Mortgage Corporation Pool 3.50% 2042-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,500	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-01	[1],[5],[6]
Fair Value			2,667	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,452 Federal National Mortgage Association Pool 3.50% 2042-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,452	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.50%	[1],[5],[6]
Maturity			2042-11	[1],[5],[6]
Fair Value			2,619	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,377 Federal National Mortgage Association Pool 4.00% 2042-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,377	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2042-06	[1],[5],[6]
Fair Value			2,564	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | Other Federal Home Loan Mortgage Corporation Pools [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	18,618	[1],[3],[4]	19,340	[1],[5],[6]
Description	Other Federal Home Loan Mortgage Corporation Pools	[1],[3],[4]	Other Federal Home Loan Mortgage Corporation Pools	[1],[5],[6]
Fair Value	19,809	[1],[3],[4]	20,744	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | Other Federal Home Loan Mortgage Corporation Pools [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	6.00%	[1],[3],[4]	6.00%	[1],[5],[6]
Maturity	2043-04	[1],[3],[4]	2042-12	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | Other Federal Home Loan Mortgage Corporation Pools [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	3.50%	[1],[3],[4]	3.50%	[1],[5],[6]
Maturity	2026-04	[1],[3],[4]	2026-04	[1],[5],[6]
Principal And Interest - Fixed Rate Agency Securities [Member] | Four Thousand One Hundred Ninety Nine Federal National Mortgage Association Pool 3 Point 50 Percent 204305 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,199	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2043-05	[1],[3],[4]
Fair Value	4,435	[1],[3],[4]
Principal And Interest - Fixed Rate Agency Securities [Member] | Four Thousand One Hundred Seventy Three Federal National Mortgage Association Pool 3 Point 50 Percent 204305 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,173	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	3.50%	[1],[3],[4]
Maturity	2043-05	[1],[3],[4]
Fair Value	4,424	[1],[3],[4]
Interest Only - Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.96%	[1],[2],[3],[4]	0.64%	[1],[2],[5],[6]
Fair Value	4,997	[1],[3],[4]	3,250	[1],[5],[6]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	16,559	[1],[3],[4]	20,095	[1],[5],[6]
Description	Other Federal National Mortgage Association	[1],[3],[4]	Other Federal National Mortgage Association	[1],[5],[6]
Fair Value	1,685	[1],[3],[4]	1,920	[1],[5],[6]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	5.50%	[1],[3],[4]	5.50%	[1],[5],[6]
Maturity	2040-10	[1],[3],[4]	2040-10	[1],[5],[6]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	4.00%	[1],[3],[4]	4.00%	[1],[5],[6]
Maturity	2036-01	[1],[3],[4]	2036-01	[1],[5],[6]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal Home Loan Mortgage Corporation [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	17,466	[1],[3],[4]	10,426	[1],[5],[6]
Description	Other Federal Home Loan Mortgage Corporation	[1],[3],[4]	Other Federal Home Loan Mortgage Corporation	[1],[5],[6]
Fair Value	2,169	[1],[3],[4]	1,195	[1],[5],[6]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal Home Loan Mortgage Corporation [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	5.50%	[1],[3],[4]	5.50%	[1],[5],[6]
Maturity	2043-01	[1],[3],[4]	2039-01	[1],[5],[6]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal Home Loan Mortgage Corporation [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	3.00%	[1],[3],[4]	5.00%	[1],[5],[6]
Maturity	2033-06	[1],[3],[4]	2033-06	[1],[5],[6]
Interest Only - Fixed Rate Agency Securities [Member] | Other Government National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	11,333	[1],[3],[4]	4,269	[1],[5],[6]
Description	Other Government National Mortgage Association	[1],[3],[4]	Other Government National Mortgage Association	[1],[5],[6]
Rate			5.50%	[1],[5],[6]
Maturity			2036-03	[1],[5],[6]
Fair Value	1,143	[1],[3],[4]	135	[1],[5],[6]
Interest Only - Fixed Rate Agency Securities [Member] | Other Government National Mortgage Association [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	5.50%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Interest Only - Fixed Rate Agency Securities [Member] | Other Government National Mortgage Association [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	3.00%	[1],[3],[4]
Maturity	2036-03	[1],[3],[4]
TBA - Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	17.28%	[1],[2],[3],[4]	8.61%	[1],[2],[5],[6]
Fair Value	89,969	[1],[3],[4]	43,610	[1],[5],[6]
TBA - Fixed Rate Agency Securities [Member] | 65,800 Federal National Mortgage Association (30 Year) 3.00% 2013-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	65,800	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation (30 Year)	[1],[3],[4]
Rate	3.00%	[1],[3],[4]
Maturity	2013-04	[1],[3],[4]
Fair Value	67,574	[1],[3],[4]
TBA - Fixed Rate Agency Securities [Member] | 18,950 Federal Home Loan Mortgage Corporation (30 Year) 4.00% 2013-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	18,950	[1],[3],[4]
Description	Federal Home Loan Mortgage Corporation (30 Year)	[1],[3],[4]
Rate	4.00%	[1],[3],[4]
Maturity	2013-04	[1],[3],[4]
Fair Value	20,143	[1],[3],[4]
TBA - Fixed Rate Agency Securities [Member] | 2,170 Federal National Mortgage Association (15 Year) 2.50% 2013-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	2,170	[1],[3],[4]
Description	Other Federal National Mortgage Association (15 Year)	[1],[3],[4]
Rate	2.50%	[1],[3],[4]
Maturity	2013-04	[1],[3],[4]
Fair Value	2,252	[1],[3],[4]
TBA - Fixed Rate Agency Securities [Member] | 18,950 Federal Home Loan Mortgage Corporation (30 Years) 4.00% 2013-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			18,950	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation (30 Year)	[1],[5],[6]
Rate			4.00%	[1],[5],[6]
Maturity			2013-01	[1],[5],[6]
Fair Value			20,232	[1],[5],[6]
TBA - Fixed Rate Agency Securities [Member] | 16,600 Federal National Mortgage Association (15 Years) 3.00% 2013-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			16,600	[1],[5],[6]
Description			Federal National Mortgage Association (15 Year)	[1],[5],[6]
Rate			3.00%	[1],[5],[6]
Maturity			2013-01	[1],[5],[6]
Fair Value			17,523	[1],[5],[6]
TBA - Fixed Rate Agency Securities [Member] | 5,600 Federal Home Loan Mortgage Corporation (30 Years) 3.00% 2013-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,600	[1],[5],[6]
Description			Federal Home Loan Mortgage Corporation (30 Year)	[1],[5],[6]
Rate			3.00%	[1],[5],[6]
Maturity			2013-01	[1],[5],[6]
Fair Value			5,855	[1],[5],[6]
Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	177.72%	[1],[2],[3],[4]	157.46%	[1],[2],[5],[6]
Fair Value	925,232	[1],[3],[4]	797,314	[1],[5],[6]
Investment Owned, at Cost	922,140	[1],[3],[4]	789,964	[1],[5],[6]
Principal And Interest - Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	2.79%	[1],[2],[3],[4]	3.39%	[1],[2],[5],[6]
Fair Value	14,512	[1],[3],[4]	17,169	[1],[5],[6]
Principal And Interest - Floating Rate Agency Securities [Member] | 5,131 Federal National Mortgage Association Pool 5.10% 2038-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,131	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	5.10%	[1],[3],[4]
Maturity	2038-05	[1],[3],[4]
Fair Value	5,410	[1],[3],[4]
Principal And Interest - Floating Rate Agency Securities [Member] | 3,526 Federal National Mortgage Association Pool 2.55% 2035-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,526	[1],[3],[4]
Description	Federal National Mortgage Association Pool	[1],[3],[4]
Rate	2.55%	[1],[3],[4]
Maturity	2035-12	[1],[3],[4]
Fair Value	3,713	[1],[3],[4]
Principal And Interest - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,063	[1],[3],[4]	3,159	[1],[5],[6]
Description	Other Federal National Mortgage Association Pools	[1],[3],[4]	Other Federal National Mortgage Association Pools	[1],[5],[6]
Fair Value	5,389	[1],[3],[4]	3,385	[1],[5],[6]
Principal And Interest - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	5.67%	[1],[3],[4]	5.50%	[1],[5],[6]
Maturity	2037-09	[1],[3],[4]	2037-09	[1],[5],[6]
Principal And Interest - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	4.93%	[1],[3],[4]	4.93%	[1],[5],[6]
Maturity	2036-04	[1],[3],[4]	2037-07	[1],[5],[6]
Principal And Interest - Floating Rate Agency Securities [Member] | 6,045 Federal National Mortgage Association Pool 5.08% 2038-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,045	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.08%	[1],[5],[6]
Maturity			2038-05	[1],[5],[6]
Fair Value			6,374	[1],[5],[6]
Principal And Interest - Floating Rate Agency Securities [Member] | 4,537 Federal National Mortgage Association Pool 3.14% 2035-15 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,537	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			3.14%	[1],[5],[6]
Maturity			2035-12	[1],[5],[6]
Fair Value			4,783	[1],[5],[6]
Principal And Interest - Floating Rate Agency Securities [Member] | 2,478 Federal National Mortgage Association Pool 5.69% 2036-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,478	[1],[5],[6]
Description			Federal National Mortgage Association Pool	[1],[5],[6]
Rate			5.69%	[1],[5],[6]
Maturity			2036-04	[1],[5],[6]
Fair Value			2,627	[1],[5],[6]
Interest Only - Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	2.16%	[1],[2],[3],[4]	0.67%	[1],[2],[5],[6]
Fair Value	11,231	[1],[3],[4]	3,394	[1],[5],[6]
Interest Only - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,301	[1],[3],[4]	1,042	[1],[5],[6]
Description	Other Federal National Mortgage Association	[1],[3],[4]	Other Federal National Mortgage Association	[1],[5],[6]
Rate			5.50%	[1],[5],[6]
Maturity			2036-08	[1],[5],[6]
Fair Value	1,042	[1],[3],[4]	152	[1],[5],[6]
Interest Only - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	6.45%	[1],[3],[4]
Maturity	2041-12	[1],[3],[4]
Interest Only - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	5.50%	[1],[3],[4]
Maturity	2036-08	[1],[3],[4]
Interest Only - Floating Rate Agency Securities [Member] | Other Government National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	47,061	[1],[3],[4]
Description	Other Government National Mortgage Association	[1],[3],[4]
Fair Value	6,915	[1],[3],[4]
Interest Only - Floating Rate Agency Securities [Member] | Other Government National Mortgage Association [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	6.55%	[1],[3],[4]
Maturity	2061-04	[1],[3],[4]
Interest Only - Floating Rate Agency Securities [Member] | Other Government National Mortgage Association [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	2.57%	[1],[3],[4]
Maturity	2042-11	[1],[3],[4]
Interest Only - Floating Rate Agency Securities [Member] | Resecuritization of Government National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	23,123	[1],[3],[4],[7]	23,140	[1],[5],[6],[7]
Description	Resecuritization of Government National Mortgage Association (o)	[1],[3],[4],[7]	Resecuritization of Government National Mortgage Association (o)	[1],[5],[6],[7]
Rate	4.28%	[1],[3],[4],[7]	4.28%	[1],[5],[6],[7]
Maturity	2060-08	[1],[3],[4],[7]	2060-08	[1],[5],[6],[7]
Fair Value	3,274	[1],[3],[4],[7]	3,242	[1],[5],[6],[7]
Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	4.95%	[1],[2],[3],[4]	4.06%	[1],[2],[5],[6]
Fair Value	25,743	[1],[3],[4]	20,563	[1],[5],[6]
Investment Owned, at Cost	25,043	[1],[3],[4]	19,979	[1],[5],[6]
Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	182.67%	[1],[2],[3],[4]	161.52%	[1],[2],[5],[6]
Fair Value	950,975	[1],[3],[4]	817,877	[1],[5],[6]
Investment Owned, at Cost	947,183	[1],[3],[4]	809,943	[1],[5],[6]
Principal And Interest - Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	107.46%	[1],[2],[3]	107.47%	[1],[2],[5]
Fair Value	559,418	[1],[3]	544,208	[1],[5]
Investment Owned, at Cost	494,043	[1],[3]	505,380	[1],[5]
Principal And Interest - Private Label Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	767,990	[1],[3]	850,320	[1],[5]
Description	Various	[1],[3]	Various	[1],[5]
Fair Value	559,418	[1],[3]	544,208	[1],[5]
Principal And Interest - Private Label Securities [Member] | Various Issuer [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	9.35%	[1],[3]	9.35%	[1],[5]
Maturity	2047-06	[1],[3]	2047-05	[1],[5]
Principal And Interest - Private Label Securities [Member] | Various Issuer [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	0.29%	[1],[3]	0.17%	[1],[5]
Maturity	2019-05	[1],[3]	2019-05	[1],[5]
Principal Only - Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.57%	[1],[2],[3]	0.46%	[2],[5]
Fair Value	2,967	[1],[3]	2,320	[1],[5]
Investment Owned, at Cost	2,297	[1],[3]	2,242	[1],[5]
Principal Only - Private Label Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,800	[1],[3]	5,800	[1],[5]
Description	Various	[1],[3]	Various	[1],[5]
Rate	0.00%	[1],[3]	0.00%	[1],[5]
Maturity	2030-08	[1],[3]	2030-08	[1],[5]
Fair Value	2,967	[1],[3]	2,320	[1],[5]
Interest Only - Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.23%	[1],[2],[3]	0.23%	[1],[2],[5]
Fair Value	1,213	[1],[3]	1,165	[1],[5]
Investment Owned, at Cost	597	[1],[3]	637	[1],[5]
Interest Only - Private Label Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	57,691	[1],[3]	61,640	[1],[5]
Description	Various	[1],[3]	Various	[1],[5]
Fair Value	1,213	[1],[3]	1,165	[1],[5]
Interest Only - Private Label Securities [Member] | Various Issuer [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	2.00%	[1],[3]	2.00%	[1],[5]
Maturity	2047-09	[1],[3]	2047-09	[1],[5]
Interest Only - Private Label Securities [Member] | Various Issuer [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	0.50%	[1],[3]	0.50%	[1],[5]
Maturity	2044-06	[1],[3]	2044-06	[1],[5]
Other Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.00%	[1],[2],[3]	0.00%	[1],[2],[5]
Fair Value	0	[1],[3]	0	[1],[5]
Investment Owned, at Cost	393	[1],[3]	429	[1],[5]
Other Private Label Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	145,163	[1],[3]	158,348	[1],[5]
Description	Various	[1],[3]	Various	[1],[5]
Rate	0.00%	[1],[3]	0.00%	[1],[5]
Maturity	2037-06	[1],[3]	2037-06	[1],[5]
Fair Value	0	[1],[3]	0	[1],[5]
Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	108.26%	[1],[2],[3]	108.16%	[1],[2],[5]
Fair Value	563,598	[1],[3]	547,693	[1],[5]
Investment Owned, at Cost	497,330	[1],[3]	508,688	[1],[5]
Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	290.93%	[1],[2],[3]	269.68%	[1],[2],[5]
Fair Value	1,514,573	[1],[3]	1,365,570	[1],[5]
Investment Owned, at Cost	1,444,513	[1],[3]	1,318,631	[1],[5]
Commercial Mortgage Loans [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	1.87%	[1],[2],[3],[8]	1.89%	[1],[2],[5],[9]
Fair Value	9,713	[1],[3],[8]	9,546	[1],[5],[9]
Investment Owned, at Cost	9,530	[1],[3],[8]	9,522	[1],[5],[9]
Commercial Mortgage Loans [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	10,225	[1],[3],[8]	10,225	[1],[5],[9]
Description	Various	[1],[3],[8]	Various	[1],[5],[9]
Fair Value	9,713	[1],[3],[8]	9,546	[1],[5],[9]
Commercial Mortgage Loans [Member] | Various Issuer [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	7.25%	[1],[3]	6.25%	[1],[5],[9]
Maturity	2039-05	[1],[3]	2039-05	[1],[5],[9]
Commercial Mortgage Loans [Member] | Various Issuer [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	0.00%	[1],[3]	5.00%	[1],[5],[9]
Maturity	2013-11	[1],[3]	2013-11	[1],[5],[9]
Asset-backed Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	2.23%	[1],[2],[3]
Fair Value	11,638	[1],[3]
Investment Owned, at Cost	11,745	[1],[3]
Asset-backed Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	15,876	[1],[3]
Description	Various	[1],[3]
Fair Value	11,638	[1],[3]
Asset-backed Securities [Member] | Various Issuer [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	5.80%	[1],[3]
Maturity	2049-12	[1],[3]
Asset-backed Securities [Member] | Various Issuer [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	0.00%	[1],[3]
Maturity	2016-05	[1],[3]
Long Investments [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	295.03%	[1],[2],[3]	271.57%	[1],[2],[5]
Fair Value	1,535,924	[1],[3]	1,375,116	[1],[5]
Investment Owned, at Cost	1,465,788	[1],[3]	1,328,153	[1],[5],[6]
Long Investments [Member] | Federal National Mortgage Association [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	116.33%		119.78%
Long Investments [Member] | Federal Home Loan Mortgage Corporation [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	51.87%		40.49%
Long Investments [Member] | Government National Mortgage Association [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	14.47%		1.25%
Commercial Mortgage Loan With Extendable Maturity [Member] | Commercial Mortgage Loans [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Fair Value	$ 5,000		$ 4,900

[1] See Note 2 and Note 3 in Notes to Consolidated Financial Statements.

[2] Classification percentages are based on Total Equity.

[3] The table below shows the ratings on the Company's long investments from Moody's, Standard and Poor's, or Fitch, as well as the Company's long investments that were unrated but affiliated with Fannie Mae, Freddie Mac, or Ginnie Mae. Ratings tend to be a lagging credit indicator; as a result, the credit quality of the Company's long investment holdings may be lower than the credit quality implied based on the ratings listed below. In situations where an investment has a split rating, the lowest provided rating is used. The ratings descriptions include ratings qualified with a "+," "-," "1," "2," or "3."Rating Description Percent ofEquityUnrated but Agency-Guaranteed 182.67%Aaa/AAA/AAA 0.01%Aa/AA/AA 0.00%A/A/A 1.29%Baa/BBB/BBB 2.41%Ba/BB/BB or below 104.70%Unrated 3.95%

[4] At March 31, 2013, the Company's long investments guaranteed by the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation, and the Government National Mortgage Association represented 116.33%, 51.87%, and 14.47% of equity, respectively.

[5] The table below shows the Company's long investment ratings from Moody's, Standard and Poor's, or Fitch, as well as the Company's long investments that were unrated but affiliated with Fannie Mae, Freddie Mac, or Ginnie Mae. Ratings tend to be a lagging credit indicator; as a result, the credit quality of the Company's long investment holdings may be lower than the credit quality implied based on the ratings listed below. In situations where an investment has a split rating, the lowest provided rating is used. The ratings descriptions include ratings qualified with a "+," "-," "1," "2," or "3."Rating Description Percent ofEquityUnrated but Agency-Guaranteed 161.52%Aaa/AAA/AAA 0.01%Aa/AA/AA 0.26%A/A/A 1.02%Baa/BBB/BBB 3.70%Ba/BB/BB or below 102.40%Unrated 2.66%

[6] At December 31, 2012, the Company’s long investments guaranteed by the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation, and the Government National Mortgage Association represented 119.78%, 40.49%, and 1.25% of equity, respectively.

[7] Private trust 100% backed by interest in Government National Mortgage Association collateralized mortgage obligation certificates.

[8] Includes a loan with a fair value in the amount of $5.0 million where the maturity date may be extended through November 4, 2015 as well as a non-performing commercial whole loan.

[9] Includes a loan with a fair value in the amount of $4.9 million where the maturity date may be extended through November 4, 2015 as well as a non-performing commercial whole loan.