Consolidated Condensed Schedule Of Investments (Long Investments) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Schedule of Investments [Line Items]
Fair Value	$ 1,375,116		$ 1,212,483
Investment Owned, at Cost	1,328,153		1,234,203
Percentage collaterallized by GNRCMO certificates	100.00%
US Treasury Securities [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity			2.72%
Unrated But Agency-Guaranteed [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	161.52%		206.07%
Long Investment AAA Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	0.01%		1.25%
Long Investment AA Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	0.26%		1.88%
Long Investment A Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	1.02%		5.44%
Long Investment BBB Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	3.70%		3.46%
Long Investment BB Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	102.40%		103.36%
Long Investment Unrated Rating [Member]
Schedule of Investments [Line Items]
Long investment holdings as a percentage of stockholders' equity	2.66%		2.71%
Principal And Interest - Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	148.21%	[1],[2],[3]	185.76%	[1],[4],[5]
Fair Value	750,454	[1],[2],[3]	689,018	[1],[4],[5]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-12	[1],[2],[3]
Fair Value	52,864	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	48,596	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2037-07	[1],[2],[3]
Fair Value	38,657	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-12	[1],[2],[3]
Fair Value	23,268	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	19,552	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-09	[1],[2],[3]
Fair Value	19,459	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2041-07	[1],[2],[3]
Fair Value	19,218	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2041-08	[1],[2],[3]
Fair Value	19,201	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-10	[1],[2],[3]
Fair Value	18,661	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2041-03	[1],[2],[3]
Fair Value	17,430	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.00%	[1],[2],[3]
Maturity	2042-10	[1],[2],[3]
Fair Value	15,642	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	15,407	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.00%	[1],[2],[3]
Maturity	2042-10	[1],[2],[3]
Fair Value	14,157	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-09	[1],[2],[3]
Fair Value	12,994	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2041-11	[1],[2],[3]
Fair Value	12,848	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2041-07	[1],[2],[3]
Fair Value	12,058	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-01	[1],[2],[3]
Fair Value	11,355	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2026-04	[1],[2],[3]
Fair Value	10,338	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-10	[1],[2],[3]
Fair Value	9,772	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-02	[1],[2],[3]
Fair Value	9,038	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.50%	[1],[2],[3]
Maturity	2039-10	[1],[2],[3]
Fair Value	8,075	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-10	[1],[2],[3]
Fair Value	7,984	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2026-07	[1],[2],[3]
Fair Value	7,888	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2041-06	[1],[2],[3]
Fair Value	6,891	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-05	[1],[2],[3]
Fair Value	6,356	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-05	[1],[2],[3]
Fair Value	6,141	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2041-10	[1],[2],[3]
Fair Value	6,079	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	6,020	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	5,862	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2041-10	[1],[2],[3]
Fair Value	5,534	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-04	[1],[2],[3]
Fair Value	5,531	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2040-11	[1],[2],[3]
Fair Value	5,497	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2041-07	[1],[2],[3]
Fair Value	5,444	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-08	[1],[2],[3]
Fair Value	5,361	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-09	[1],[2],[3]
Fair Value	5,242	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-09	[1],[2],[3]
Fair Value	5,059	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-07	[1],[2],[3]
Fair Value	5,042	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2026-06	[1],[2],[3]
Fair Value	5,041	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	4,828	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-02	[1],[2],[3]
Fair Value	4,787	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.00%	[1],[2],[3]
Maturity	2027-07	[1],[2],[3]
Fair Value	4,710	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	4,573	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2041-11	[1],[2],[3]
Fair Value	4,303	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	4,229	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	4,189	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2035-10	[1],[2],[3]
Fair Value	4,172	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-10	[1],[2],[3]
Fair Value	4,116	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.00%	[1],[2],[3]
Maturity	2040-06	[1],[2],[3]
Fair Value	4,062	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-12	[1],[2],[3]
Fair Value	4,040	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2027-06	[1],[2],[3]
Fair Value	4,022	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.00%	[1],[2],[3]
Maturity	2027-08	[1],[2],[3]
Fair Value	3,980	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2042-04	[1],[2],[3]
Fair Value	3,941	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	6.00%	[1],[2],[3]
Maturity	2039-04	[1],[2],[3]
Fair Value	3,848	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-12	[1],[2],[3]
Fair Value	3,770	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-09	[1],[2],[3]
Fair Value	3,737	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	3,712	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-04	[1],[2],[3]
Fair Value	3,706	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-01	[1],[2],[3]
Fair Value	3,653	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-09	[1],[2],[3]
Fair Value	3,618	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.00%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	3,573	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-02	[1],[2],[3]
Fair Value	3,518	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	3,440	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-11	[1],[2],[3]
Fair Value	3,355	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	3,262	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	3,178	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2027-07	[1],[2],[3]
Fair Value	3,145	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2027-06	[1],[2],[3]
Fair Value	3,123	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-10	[1],[2],[3]
Fair Value	3,076	[1],[2],[3]
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],[2],[3]
Description	Government National Mortgage Association	[1],[2],[3]
Rate	4.55%	[1],[2],[3]
Maturity	2062-10	[1],[2],[3]
Fair Value	2,977	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2041-10	[1],[2],[3]
Fair Value	2,901	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	2,774	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.50%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	2,719	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-09	[1],[2],[3]
Fair Value	2,699	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	2,690	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	2,685	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-08	[1],[2],[3]
Fair Value	2,679	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-01	[1],[2],[3]
Fair Value	2,667	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.50%	[1],[2],[3]
Maturity	2042-11	[1],[2],[3]
Fair Value	2,619	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2042-06	[1],[2],[3]
Fair Value	2,564	[1],[2],[3]
Principal And Interest - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	69,330	[1],[2],[3]	4,609	[1],[4],[5]
Description	Other Federal National Mortgage Association Pools	[1],[2],[3]	Other Federal National Mortgage Association Pools	[1],[4],[5]
Rate			6.00%	[1],[4],[5]
Fair Value	74,508	[1],[2],[3]	5,092	[1],[4],[5]
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],[2],[3]
Maturity	2043-01	[1],[2],[3]	2040-02	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	2.50%	[1],[2],[3]
Maturity	2026-03	[1],[2],[3]	2039-09	[1],[4],[5]
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	19,340	[1],[2],[3]
Description	Other Federal Home Loan Mortgage Corporation Pools	[1],[2],[3]
Fair Value	20,744	[1],[2],[3]
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],[2],[3]
Maturity	2042-12	[1],[2],[3]
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],[2],[3]
Maturity	2026-04	[1],[2],[3]
Principal And Interest - Fixed Rate Agency Securities [Member] | 85,000 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			85,000	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			90,611	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 25,882 Federal National Mortgage Association Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			25,882	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-07	[1],[4],[5]
Fair Value			28,107	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 25,456 Federal Home Loan Mortgage Corporation Pool 4.00% 2040-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			25,456	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2040-11	[1],[4],[5]
Fair Value			26,824	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 24,164 Federal National Mortgage Association Pool 4.50% 2041-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			24,164	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-12	[1],[4],[5]
Fair Value			25,874	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 20,212 Federal National Mortgage Association Pool 5.00% 2041-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			20,212	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-08	[1],[4],[5]
Fair Value			21,937	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 18,867 Federal Home Loan Mortgage Corporation Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			18,867	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-07	[1],[4],[5]
Fair Value			20,417	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 18,434 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			18,434	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			19,738	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 18,120 Federal National Mortgage Association Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			18,120	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			19,397	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,391 Federal National Mortgage Association Pool 5.00% 2041-03 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			17,391	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-03	[1],[4],[5]
Fair Value			18,941	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 17,182 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			17,182	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			18,328	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 15,465 Federal Home Loan Mortgage Corporation Pool 5.00% 2039-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			15,465	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2039-09	[1],[4],[5]
Fair Value			16,620	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 15,243 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			15,243	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			16,260	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 14,964 Federal National Mortgage Association Pool 4.50% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			14,964	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-11	[1],[4],[5]
Fair Value			15,991	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 13,451 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			13,451	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			14,348	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 13,554 Federal National Mortgage Association Pool 4.00% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			13,554	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-11	[1],[4],[5]
Fair Value			14,252	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 13,033 Federal National Mortgage Association Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			13,033	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			13,927	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 13,125 Federal National Mortgage Association Pool 4.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			13,125	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			13,818	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 12,593 Federal National Mortgage Association Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			12,593	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-07	[1],[4],[5]
Fair Value			13,699	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 11,361 Federal National Mortgage Association Pool 4.50% 2026-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			11,361	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2026-04	[1],[4],[5]
Fair Value			12,154	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 11,095 Federal National Mortgage Association Pool 5.00% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			11,095	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			12,098	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 10,358 Federal Home Loan Mortgage Corporation Pool 4.00% 2041-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			10,358	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-01	[1],[4],[5]
Fair Value			10,902	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,995 Federal Home Loan Mortgage Corporation Pool 5.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,995	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			10,791	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,468 Federal National Mortgage Association Pool 4.00% 2026-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,468	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2026-07	[1],[4],[5]
Fair Value			10,011	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,176 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,176	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-02	[1],[4],[5]
Fair Value			9,805	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,149 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,149	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			9,736	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,152 Federal National Mortgage Association Pool 4.00% 2026-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,152	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2026-05	[1],[4],[5]
Fair Value			9,657	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 9,027 Federal National Mortgage Association Pool 4.00% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,027	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			9,498	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 8,468 Federal National Mortgage Association Pool 5.50% 2039-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			8,468	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.50%	[1],[4],[5]
Maturity			2039-10	[1],[4],[5]
Fair Value			9,269	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 8,400 Federal Home Loan Mortgage Corporation Pool 4.00% 2041-03 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			8,400	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-03	[1],[4],[5]
Fair Value			8,851	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 8,123 Federal National Mortgage Association Pool 5.00% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			8,123	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			8,836	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 7,437 Federal National Mortgage Association Pool 5.00% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			7,437	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			8,072	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 7,261 Federal National Mortgage Association Pool 5.50% 2040-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			7,261	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.50%	[1],[4],[5]
Maturity			2040-05	[1],[4],[5]
Fair Value			7,947	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 6,955 Federal National Mortgage Association Pool 5.00% 2041-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,955	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-06	[1],[4],[5]
Fair Value			7,553	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 6,878 Federal National Mortgage Association Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,878	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-07	[1],[4],[5]
Fair Value			7,465	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 6,852 Federal National Mortgage Association Pool 5.00% 2041-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,852	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-05	[1],[4],[5]
Fair Value			7,437	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 6,823 Federal National Mortgage Association Pool 5.00% 2041-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,823	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-06	[1],[4],[5]
Fair Value			7,406	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 6,759 Federal National Mortgage Association Pool 4.00% 2026-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,759	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2026-06	[1],[4],[5]
Fair Value			7,147	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,836 Federal National Mortgage Association Pool 5.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,836	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			6,334	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,531 Federal Home Loan Mortgage Corporation Pool 6.00% 2039-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,531	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			6.00%	[1],[4],[5]
Maturity			2039-04	[1],[4],[5]
Fair Value			6,095	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,687 Federal National Mortgage Association Pool 4.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,687	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			5,987	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,514 Federal National Mortgage Association Pool 5.00% 2040-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,514	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2040-11	[1],[4],[5]
Fair Value			5,985	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,711 Federal National Mortgage Association Pool 3.50% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,711	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			3.50%	[1],[4],[5]
Maturity			2041-11	[1],[4],[5]
Fair Value			5,883	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,549 Federal Home Loan Mortgage Corporation Pool 4.00% 2041-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,549	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-05	[1],[4],[5]
Fair Value			5,833	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 5,209 Federal National Mortgage Association Pool 4.50% 2041-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			5,209	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-08	[1],[4],[5]
Fair Value			5,557	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,888 Federal National Mortgage Association Pool 5.00% 2041-08 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,888	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-08	[1],[4],[5]
Fair Value			5,330	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,799 Federal National Mortgage Association Pool 5.00% 2040-06 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,799	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2040-06	[1],[4],[5]
Fair Value			5,209	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,837 Federal National Mortgage Association Pool 4.50% 2041-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,837	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-04	[1],[4],[5]
Fair Value			5,190	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,702 Federal National Mortgage Association Pool 5.00% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,702	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			5,127	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,398 Federal Home Loan Mortgage Corporation Pool 3.50% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,398	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			3.50%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			4,522	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,150 Federal National Mortgage Association Pool 5.00% 2041-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,150	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-10	[1],[4],[5]
Fair Value			4,504	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,230 Federal National Mortgage Association Pool 4.00% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,230	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			4,454	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,158 Federal Home Loan Mortgage Corporation Pool 4.00% 2041-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,158	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2041-01	[1],[4],[5]
Fair Value			4,384	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 4,100 Federal National Mortgage Association Pool 4.50% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			4,100	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-11	[1],[4],[5]
Fair Value			4,374	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,724 Federal Home Loan Mortgage Corporation Pool 4.50% 2041-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,724	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			4.50%	[1],[4],[5]
Maturity			2041-09	[1],[4],[5]
Fair Value			3,963	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 3,751 Federal National Mortgage Association Pool 3.50% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,751	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			3.50%	[1],[4],[5]
Maturity			2041-11	[1],[4],[5]
Fair Value			3,859	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,565 Federal National Mortgage Association Pool 5.00% 2041-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,565	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-07	[1],[4],[5]
Fair Value			2,791	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 2,391 Federal National Mortgage Association Pool 5.00% 2041-11 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			2,391	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.00%	[1],[4],[5]
Maturity			2041-11	[1],[4],[5]
Fair Value			2,595	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 1,197 Other Federal Home Loan Mortgage Corporation Pool 6.00% 2040-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			1,197	[1],[4],[5]
Description			Other Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			6.00%	[1],[4],[5]
Maturity			2040-05	[1],[4],[5]
Fair Value			1,319	[1],[4],[5]
Principal And Interest - Fixed Rate Agency Securities [Member] | 806 Other Government National Mortgage Association Pool 5.50% 2041-03 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			806	[1],[4],[5]
Description			Other Government National Mortgage Association Pool	[1],[4],[5]
Rate			5.50%	[1],[4],[5]
Maturity			2041-03	[1],[4],[5]
Fair Value			907	[1],[4],[5]
Interest Only - Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.64%	[1],[2],[3]	1.38%	[1],[4],[5]
Fair Value	3,250	[1],[2],[3]	5,109	[1],[4],[5]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	20,095	[1],[2],[3]	24,381	[1],[4],[5]
Description	Other Federal National Mortgage Association	[1],[2],[3]	Other Federal National Mortgage Association	[1],[4],[5]
Fair Value	1,920	[1],[2],[3]	2,734	[1],[4],[5]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	5.50%	[1],[2],[3]	5.50%	[1],[4],[5]
Maturity	2040-10	[1],[2],[3]	2040-10	[1],[4],[5]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	4.00%	[1],[2],[3]	5.00%	[1],[4],[5]
Maturity	2036-01	[1],[2],[3]	2036-01	[1],[4],[5]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal Home Loan Mortgage Corporation [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	10,426	[1],[2],[3]	13,937	[1],[4],[5]
Description	Other Federal Home Loan Mortgage Corporation	[1],[2],[3]	Other Federal Home Loan Mortgage Corporation	[1],[4],[5]
Fair Value	1,195	[1],[2],[3]	1,772	[1],[4],[5]
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],[2],[3]	5.50%	[1],[4],[5]
Maturity	2039-01	[1],[2],[3]	2039-01	[1],[4],[5]
Interest Only - Fixed Rate Agency Securities [Member] | Other Federal Home Loan Mortgage Corporation [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	5.00%	[1],[2],[3]	5.00%	[1],[4],[5]
Maturity	2033-06	[1],[2],[3]	2033-06	[1],[4],[5]
Interest Only - Fixed Rate Agency Securities [Member] | Other Government National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	4,269	[1],[2],[3]	9,281	[1],[4],[5]
Description	Other Government National Mortgage Association	[1],[2],[3]	Other Government National Mortgage Association	[1],[4],[5]
Rate	5.50%	[1],[2],[3]	5.50%	[1],[4],[5]
Maturity	2036-03	[1],[2],[3]	2036-03	[1],[4],[5]
Fair Value	135	[1],[2],[3]	603	[1],[4],[5]
TBA - Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	8.61%	[1],[2],[3]	8.64%	[1],[4],[5]
Fair Value	43,610	[1],[2],[3]	32,033	[1],[4],[5]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation (30 Year)	[1],[2],[3]
Rate	4.00%	[1],[2],[3]
Maturity	2013-01	[1],[2],[3]
Fair Value	20,232	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association (15 Year)	[1],[2],[3]
Rate	3.00%	[1],[2],[3]
Maturity	2013-01	[1],[2],[3]
Fair Value	17,523	[1],[2],[3]
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],[2],[3]
Description	Federal Home Loan Mortgage Corporation (30 Year)	[1],[2],[3]
Rate	3.00%	[1],[2],[3]
Maturity	2013-01	[1],[2],[3]
Fair Value	5,855	[1],[2],[3]
TBA - Fixed Rate Agency Securities [Member] | 30,500 Federal National Mortgage Association (30 Year) 4.00% 2012-01 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			30,500	[1],[4],[5]
Description			Federal National Mortgage Association (30 Year)	[1],[4],[5]
Rate			4.00%	[1],[4],[5]
Maturity			2012-01	[1],[4],[5]
Fair Value			32,033	[1],[4],[5]
Fixed Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	157.46%	[1],[2],[3]	195.78%	[1],[4],[5]
Fair Value	797,314	[1],[2],[3]	726,160	[1],[4],[5]
Investment Owned, at Cost	789,964	[1],[2],[3]	718,177	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	3.39%	[1],[2],[3]	10.23%	[1],[4],[5]
Fair Value	17,169	[1],[2],[3]	37,956	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	3,159	[1],[2],[3]
Description	Other Federal National Mortgage Association Pools	[1],[2],[3]
Fair Value	3,385	[1],[2],[3]
Principal And Interest - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association Pools Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	5.50%	[1],[2],[3]
Maturity	2037-09	[1],[2],[3]
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],[2],[3]
Maturity	2037-07	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.08%	[1],[2],[3]
Maturity	2038-05	[1],[2],[3]
Fair Value	6,374	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	3.14%	[1],[2],[3]
Maturity	2035-12	[1],[2],[3]
Fair Value	4,783	[1],[2],[3]
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],[2],[3]
Description	Federal National Mortgage Association Pool	[1],[2],[3]
Rate	5.69%	[1],[2],[3]
Maturity	2036-04	[1],[2],[3]
Fair Value	2,627	[1],[2],[3]
Principal And Interest - Floating Rate Agency Securities [Member] | 9,464 Federal National Mortgage Association Pool 5.10% 2038-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			9,464	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.10%	[1],[4],[5]
Maturity			2038-05	[1],[4],[5]
Fair Value			9,969	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member] | 6,675 Federal National Mortgage Association Pool 5.28% 2035-12 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,675	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.28%	[1],[4],[5]
Maturity			2035-12	[1],[4],[5]
Fair Value			7,027	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member] | 6,627 Federal National Mortgage Association Pool 5.29% 2038-02 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			6,627	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.29%	[1],[4],[5]
Maturity			2038-02	[1],[4],[5]
Fair Value			6,954	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member] | 3,364 Federal Home Loan Mortgage Corporation Pool 2.71% 2034-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,364	[1],[4],[5]
Description			Federal Home Loan Mortgage Corporation Pool	[1],[4],[5]
Rate			2.71%	[1],[4],[5]
Maturity			2034-07	[1],[4],[5]
Fair Value			3,524	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member] | 3,261 Federal National Mortgage Association Pool 5.52% 2037-07 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,261	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.52%	[1],[4],[5]
Maturity			2037-07	[1],[4],[5]
Fair Value			3,493	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member] | 3,247 Federal National Mortgage Association Pool 5.69% 2036-04 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			3,247	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.69%	[1],[4],[5]
Maturity			2036-04	[1],[4],[5]
Fair Value			3,441	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member] | 1,906 Federal National Mortgage Association Pool 5.44% 2037-09 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			1,906	[1],[4],[5]
Description			Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.44%	[1],[4],[5]
Maturity			2037-09	[1],[4],[5]
Fair Value			2,023	[1],[4],[5]
Principal And Interest - Floating Rate Agency Securities [Member] | 1,444 Other Federal National Mortgage Association Pool 5.01% 2033-10 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			1,444	[1],[4],[5]
Description			Other Federal National Mortgage Association Pool	[1],[4],[5]
Rate			5.01%	[1],[4],[5]
Maturity			2033-10	[1],[4],[5]
Fair Value			1,525	[1],[4],[5]
Interest Only - Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.67%	[1],[2],[3]	0.06%	[1],[4],[5]
Fair Value	3,394	[1],[2],[3]	228	[1],[4],[5]
Interest Only - Floating Rate Agency Securities [Member] | Other Federal National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	1,042	[1],[2],[3]	1,476	[1],[4],[5]
Description	Other Federal National Mortgage Association	[1],[2],[3]	Other Federal National Mortgage Association Pool	[1],[4],[5]
Rate	5.50%	[1],[2],[3]	5.50%	[1],[4],[5]
Maturity	2036-08	[1],[2],[3]	2036-08	[1],[4],[5]
Fair Value	152	[1],[2],[3]	228	[1],[4],[5]
Interest Only - Floating Rate Agency Securities [Member] | Resecuritization of Government National Mortgage Association [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	23,140	[1],[2],[3],[6]
Description	Resecuritization of Government National Mortgage Association (o)	[1],[2],[3],[6]
Rate	4.28%	[1],[2],[3],[6]
Maturity	2060-08	[1],[2],[3],[6]
Fair Value	3,242	[1],[2],[3],[6]
Floating Rate Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	4.06%	[1],[2],[3]	10.29%	[1],[4],[5]
Fair Value	20,563	[1],[2],[3]	38,184	[1],[4],[5]
Investment Owned, at Cost	19,979	[1],[2],[3]	37,594	[1],[4],[5]
Agency Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	161.52%	[1],[2],[3]	206.07%	[1],[4],[5]
Fair Value	817,877	[1],[2],[3]	764,344	[1],[4],[5]
Investment Owned, at Cost	809,943	[1],[2],[3]	755,771	[1],[4],[5]
Principal And Interest - Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	107.47%	[1],[2]	114.91%	[1],[4]
Fair Value	544,208	[1],[2]	426,202	[1],[4]
Investment Owned, at Cost	505,380	[1],[2]	456,170	[1],[4]
Principal And Interest - Private Label Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	850,320	[1],[2]	762,480	[1],[4]
Description	Various	[1],[2]	Various	[1],[4]
Fair Value	544,208	[1],[2]	426,202	[1],[4]
Principal And Interest - Private Label Securities [Member] | Various Issuer [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	9.35%	[1],[2]	9.35%	[1],[4]
Maturity	2047-05	[1],[2]	2047-12	[1],[4]
Principal And Interest - Private Label Securities [Member] | Various Issuer [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	0.17%	[1],[2]	0.35%
Maturity	2019-05	[1],[2]	2019-05	[1],[4]
Principal Only - Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.46%	[1],[2]
Fair Value	2,320	[1],[2]
Investment Owned, at Cost	2,242	[1],[2]
Principal Only - Private Label Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	5,800	[1],[2]
Description	Various	[1],[2]
Rate	0.00%	[1],[2]
Maturity	2030-08	[1],[2]
Fair Value	2,320	[1],[2]
Interest Only - Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.23%	[1],[2]	0.48%	[1],[4]
Fair Value	1,165	[1],[2]	1,774	[1],[4]
Investment Owned, at Cost	637	[1],[2]	1,471	[1],[4]
Interest Only - Private Label Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	61,640	[1],[2]	76,167	[1],[4]
Description	Various	[1],[2]	Various	[1],[4]
Fair Value	1,165	[1],[2]	1,774	[1],[4]
Interest Only - Private Label Securities [Member] | Various Issuer [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	2.00%	[1],[2]	6.91%	[1],[4]
Maturity	2047-09	[1],[2]	2047-09	[1],[4]
Interest Only - Private Label Securities [Member] | Various Issuer [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	0.50%	[1],[2]	0.50%	[1],[4]
Maturity	2044-06	[1],[2]	2035-07	[1],[4]
Other Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	0.00%	[1],[2]	1.52%	[1],[4]
Fair Value	0	[1],[2]	5,650	[1],[4]
Investment Owned, at Cost	429	[1],[2]	6,011	[1],[4]
Other Private Label Securities [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	158,348	[1],[2]	201,831	[1],[4]
Description	Various	[1],[2]	Various	[1],[4]
Rate	0.00%	[1],[2]	0.00%	[1],[4]
Maturity	2037-06	[1],[2]
Fair Value	0	[1],[2]	5,650	[1],[4]
Other Private Label Securities [Member] | Various Issuer [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Maturity			2046-09	[1],[4]
Other Private Label Securities [Member] | Various Issuer [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Maturity			2037-06	[1],[4]
Private Label Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	108.16%	[1],[2]	116.91%	[1],[4]
Fair Value	547,693	[1],[2]	433,626	[1],[4]
Investment Owned, at Cost	508,688	[1],[2]	463,652	[1],[4]
Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	269.68%	[1],[2]	322.98%	[1],[4]
Fair Value	1,365,570	[1],[2]	1,197,970	[1],[4]
Investment Owned, at Cost	1,318,631	[1],[2]	1,219,423	[1],[4]
Commercial Mortgage Loans [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	1.89%	[1],[2],[7]	1.19%	[1],[4],[8]
Fair Value	9,546	[1],[2],[7]	4,400	[1],[4],[8]
Investment Owned, at Cost	9,522	[1],[2],[7]	4,789	[1],[4],[8]
Commercial Mortgage Loans [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount	10,225	[1],[2],[7]	5,000	[1],[4],[8]
Description	Various	[1],[2],[7]	Various	[1],[4],[8]
Rate			6.25%	[1],[4],[8]
Maturity			2012-11	[1],[4],[8]
Fair Value	9,546	[1],[2],[7]	4,400	[1],[4],[8]
Commercial Mortgage Loans [Member] | Various Issuer [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Rate	6.25%	[1],[2],[7]
Maturity	2039-05	[1],[2],[7]
Commercial Mortgage Loans [Member] | Various Issuer [Member] | Minimum [Member]
Schedule of Investments [Line Items]
Rate	5.00%	[1],[2],[7]
Maturity	2013-11	[1],[2],[7]
US Treasury Securities [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets			2.72%	[1],[4]
Fair Value			10,113	[1],[4]
Investment Owned, at Cost			9,991	[1],[4]
US Treasury Securities [Member] | US Treasury Note [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount			10,000	[1],[4]
Description			U.S. Treasury Note	[1],[4]
Rate			2.00%	[1],[4]
Maturity			2021-11	[1],[4]
Fair Value			10,113	[1],[4]
Long Investments [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	271.57%	[1],[2]	326.89%	[1],[4]
Fair Value	1,375,116	[1],[2]	1,212,483	[1],[4]
Investment Owned, at Cost	1,328,153	[1],[2]	1,234,203	[1],[2]
Long Investments [Member] | Federal National Mortgage Association [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	119.78%		142.04%
Long Investments [Member] | Federal Home Loan Mortgage Corporation [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	40.49%		63.62%
Long Investments [Member] | Government National Mortgage Association [Member]
Schedule of Investments [Line Items]
Investment owned as a percentage of net assets	1.25%		0.41%
Commercial Mortgage Loan With Extendable Maturity [Member] | Commercial Mortgage Loans [Member] | Various Issuer [Member]
Schedule of Investments [Line Items]
Fair Value	$ 4,900

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

[2] 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 DescriptionPercent ofShareholders’EquityUnrated but Agency-Guaranteed161.52%Aaa/AAA/AAA0.01%Aa/AA/AA0.26%A/A/A1.02%Baa/BBB/BBB3.70%Ba/BB/BB or below102.40%Unrated2.66%

[3] 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 shareholders’ equity, respectively.

[4] 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 DescriptionPercent ofShareholders’EquityU.S. Treasury Securities2.72%Unrated but Agency-Guaranteed206.07%Aaa/AAA/AAA1.25%Aa/AA/AA1.88%A/A/A5.44%Baa/BBB/BBB3.46%Ba/BB/BB or below103.36%Unrated2.71%

[5] At December 31, 2011, 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 142.04%, 63.62%, and 0.41% of shareholders’ equity, respectively.

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

[7] 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.

[8] Maturity date may be extended through November 4, 2015.