Mortgage Revenue Bonds - Schedule of investments in MRBs (Details) - USD ($)		Sep. 30, 2021	Dec. 31, 2020
Mortgage Revenue Bonds Held In Trust [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		$ 615,938,365	$ 637,948,068
Cumulative Unrealized Gain		111,887,768	130,520,576
Estimated Fair Value		727,826,133	768,468,644
Mortgage Revenue Bonds Held In Trust [Member] | Courtyard [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	9,993,374	10,061,161
Cumulative Unrealized Gain	[1]	2,104,001	2,487,317
Estimated Fair Value	[1]	12,097,375	12,548,478
Mortgage Revenue Bonds Held In Trust [Member] | Glenview Apartments [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[2]	4,443,092	4,483,154
Cumulative Unrealized Gain	[2]	908,843	1,010,425
Estimated Fair Value	[2]	5,351,935	5,493,579
Mortgage Revenue Bonds Held In Trust [Member] | Harmony Court Bakersfield [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	3,643,723	3,668,439
Cumulative Unrealized Gain	[1]	735,305	889,216
Estimated Fair Value	[1]	4,379,028	4,557,655
Mortgage Revenue Bonds Held In Trust [Member] | Harmony Terrace [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	6,745,564	6,791,096
Cumulative Unrealized Gain	[1]	1,461,331	1,724,350
Estimated Fair Value	[1]	8,206,895	8,515,446
Mortgage Revenue Bonds Held In Trust [Member] | Harden Ranch [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	6,559,492	6,621,823
Cumulative Unrealized Gain	[3]	1,375,319	1,606,690
Estimated Fair Value	[3]	7,934,811	8,228,513
Mortgage Revenue Bonds Held In Trust [Member] | Las Palmas II [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	1,653,240	1,664,566
Cumulative Unrealized Gain	[1]	338,062	400,431
Estimated Fair Value	[1]	1,991,302	2,064,997
Mortgage Revenue Bonds Held In Trust [Member] | Montclair Apartments [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[2]	2,407,071	2,428,775
Cumulative Unrealized Gain	[2]	492,371	572,671
Estimated Fair Value	[2]	2,899,442	3,001,446
Mortgage Revenue Bonds Held In Trust [Member] | Montecito at Williams Ranch Apartments [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	7,583,121	7,626,287
Cumulative Unrealized Gain	[4]	1,986,677	2,350,276
Estimated Fair Value	[4]	9,569,798	9,976,563
Mortgage Revenue Bonds Held In Trust [Member] | Ocotillo Springs [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	10,070,000	2,023,500
Cumulative Unrealized Gain	[4]	211,967	215,633
Estimated Fair Value	[4]	10,281,967	2,239,133
Mortgage Revenue Bonds Held In Trust [Member] | Montevista [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	6,712,763	6,720,000
Cumulative Unrealized Gain	[4]	2,094,223	2,404,771
Estimated Fair Value	[4]	8,806,986	9,124,771
Mortgage Revenue Bonds Held In Trust [Member] | San Vicente [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	3,408,893	3,432,246
Cumulative Unrealized Gain	[1]	682,336	809,327
Estimated Fair Value	[1]	4,091,229	4,241,573
Mortgage Revenue Bonds Held In Trust [Member] | Santa Fe Apartments [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[2]	2,916,076	2,942,370
Cumulative Unrealized Gain	[2]	596,489	724,678
Estimated Fair Value	[2]	3,512,565	3,667,048
Mortgage Revenue Bonds Held In Trust [Member] | Seasons at Simi Valley [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	4,200,917	4,236,876
Cumulative Unrealized Gain	[1]	1,032,960	1,180,122
Estimated Fair Value	[1]	5,233,877	5,416,998
Mortgage Revenue Bonds Held In Trust [Member] | Seasons Lakewood [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	7,185,492	7,233,993
Cumulative Unrealized Gain	[1]	1,556,635	1,836,808
Estimated Fair Value	[1]	8,742,127	9,070,801
Mortgage Revenue Bonds Held In Trust [Member] | Seasons San Juan Capistrano [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	12,098,022	12,179,682
Cumulative Unrealized Gain	[1]	2,620,866	2,973,846
Estimated Fair Value	[1]	14,718,888	15,153,528
Mortgage Revenue Bonds Held In Trust [Member] | Summerhill [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	6,274,432	6,316,993
Cumulative Unrealized Gain	[1]	1,184,799	1,470,689
Estimated Fair Value	[1]	7,459,231	7,787,682
Mortgage Revenue Bonds Held In Trust [Member] | Sycamore Walk [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	3,485,656	3,517,919
Cumulative Unrealized Gain	[1]	735,059	888,485
Estimated Fair Value	[1]	4,220,715	4,406,404
Mortgage Revenue Bonds Held In Trust [Member] | The Village at Madera [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	3,013,642	3,034,084
Cumulative Unrealized Gain	[1]	634,491	735,450
Estimated Fair Value	[1]	3,648,133	3,769,534
Mortgage Revenue Bonds Held In Trust [Member] | Tyler Park Townhomes [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	5,713,008	5,767,938
Cumulative Unrealized Gain	[3]	765,866	939,214
Estimated Fair Value	[3]	6,478,874	6,707,152
Mortgage Revenue Bonds Held In Trust [Member] | Vineyard Gardens | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	3,947,054	3,969,173
Cumulative Unrealized Gain	[4]	997,673	1,226,058
Estimated Fair Value	[4]	4,944,727	5,195,231
Mortgage Revenue Bonds Held In Trust [Member] | Westside Village Market [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	3,733,442	3,769,337
Cumulative Unrealized Gain	[3]	727,207	859,860
Estimated Fair Value	[3]	4,460,649	4,629,197
Mortgage Revenue Bonds Held In Trust [Member] | Brookstone [Member] | IL [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[5]	7,344,918	7,374,252
Cumulative Unrealized Gain	[5]	1,847,424	2,201,663
Estimated Fair Value	[5]	9,192,342	9,575,915
Mortgage Revenue Bonds Held In Trust [Member] | Copper Gate Apartments [Member] | IN [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	4,955,000	4,955,000
Cumulative Unrealized Gain	[3]	495,838	641,581
Estimated Fair Value	[3]	5,450,838	5,596,581
Mortgage Revenue Bonds Held In Trust [Member] | Renaissance [Member] | Series A [Member] | LA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[2]	10,767,672	10,870,681
Cumulative Unrealized Gain	[2]	3,942,658	4,293,328
Estimated Fair Value	[2]	14,710,330	15,164,009
Mortgage Revenue Bonds Held In Trust [Member] | Live 929 Apartments [Member] | MD [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	36,185,509	36,234,756
Estimated Fair Value	[4]	36,185,509	36,234,756
Mortgage Revenue Bonds Held In Trust [Member] | Woodlynn Village [Member] | MN [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[5]	4,093,000	4,120,000
Cumulative Unrealized Gain	[5]	14,225	56,458
Estimated Fair Value	[5]	4,107,225	4,176,458
Mortgage Revenue Bonds Held In Trust [Member] | Gateway Village [Member] | NC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	2,600,000	2,600,000
Cumulative Unrealized Gain	[4]	132,943	136,612
Estimated Fair Value	[4]	2,732,943	2,736,612
Mortgage Revenue Bonds Held In Trust [Member] | Greens Property [Member] | Series A [Member] | NC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	7,748,000	7,829,000
Cumulative Unrealized Gain	[3]	378,239	663,781
Estimated Fair Value	[3]	8,126,239	8,492,781
Mortgage Revenue Bonds Held In Trust [Member] | Lynnhaven Apartments [Member] | NC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	3,450,000	3,450,000
Cumulative Unrealized Gain	[4]	176,406	178,960
Estimated Fair Value	[4]	3,626,406	3,628,960
Mortgage Revenue Bonds Held In Trust [Member] | Silver Moon [Member] | Series A [Member] | NM [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[2]	7,647,135	7,697,891
Cumulative Unrealized Gain	[2]	1,797,774	1,995,694
Estimated Fair Value	[2]	9,444,909	9,693,585
Mortgage Revenue Bonds Held In Trust [Member] | Jackson Manor Apartments [member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	4,900,000
Estimated Fair Value	[4]	4,900,000
Mortgage Revenue Bonds Held In Trust [Member] | Village at Avalon [Member] | Series A [Member] | NM [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[6]	16,099,958	16,189,074
Cumulative Unrealized Gain	[6]	4,093,405	4,879,623
Estimated Fair Value	[6]	20,193,363	21,068,697
Mortgage Revenue Bonds Held In Trust [Member] | Ohio Properties [Member] | Series A [Member] | OH [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[5]	13,616,000	13,724,000
Cumulative Unrealized Gain	[5]		61,243
Estimated Fair Value	[5]	13,616,000	13,785,243
Mortgage Revenue Bonds Held In Trust [Member] | Bridle Ridge [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[5]	7,145,000	7,235,000
Cumulative Unrealized Gain	[5]	73,927	153,657
Estimated Fair Value	[5]	7,218,927	7,388,657
Mortgage Revenue Bonds Held In Trust [Member] | Columbia Gardens [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	12,769,035	12,898,904
Cumulative Unrealized Gain	[1]	2,149,253	2,689,886
Estimated Fair Value	[1]	14,918,288	15,588,790
Mortgage Revenue Bonds Held In Trust [Member] | Companion at Thornhill Apartments [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	10,957,982	11,055,254
Cumulative Unrealized Gain	[1]	1,913,654	2,208,446
Estimated Fair Value	[1]	12,871,636	13,263,700
Mortgage Revenue Bonds Held In Trust [Member] | Cross Creek [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[5]	6,125,082	6,136,261
Cumulative Unrealized Gain	[5]	1,953,483	2,277,289
Estimated Fair Value	[5]	8,078,565	8,413,550
Mortgage Revenue Bonds Held In Trust [Member] | The Palms at Premier Park [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	18,445,321	18,619,081
Cumulative Unrealized Gain	[3]	2,419,261	2,906,879
Estimated Fair Value	[3]	20,864,582	21,525,960
Mortgage Revenue Bonds Held In Trust [Member] | Village at River's Edge [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	9,747,304	9,802,479
Cumulative Unrealized Gain	[1]	2,034,411	1,353,745
Estimated Fair Value	[1]	11,781,715	11,156,224
Mortgage Revenue Bonds Held In Trust [Member] | Willow Run [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	12,592,729	12,720,560
Cumulative Unrealized Gain	[1]	2,005,382	2,650,995
Estimated Fair Value	[1]	14,598,111	15,371,555
Mortgage Revenue Bonds Held In Trust [Member] | Arbors at Hickory Ridge [Member] | TN [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	10,795,450	10,910,733
Cumulative Unrealized Gain	[3]	3,772,762	2,704,295
Estimated Fair Value	[3]	14,568,212	13,615,028
Mortgage Revenue Bonds Held In Trust [Member] | Avistar at Copperfield [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	13,713,412	13,815,817
Cumulative Unrealized Gain	[4]	2,499,600	3,189,896
Estimated Fair Value	[4]	16,213,012	17,005,713
Mortgage Revenue Bonds Held In Trust [Member] | Avistar at the Crest [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	9,052,461	9,140,656
Cumulative Unrealized Gain	[3]	1,874,594	2,376,580
Estimated Fair Value	[3]	10,927,055	11,517,236
Mortgage Revenue Bonds Held In Trust [Member] | Avistar at the Oaks [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	7,319,090	7,388,262
Cumulative Unrealized Gain	[3]	1,578,486	1,854,785
Estimated Fair Value	[3]	8,897,576	9,243,047
Mortgage Revenue Bonds Held In Trust [Member] | Avistar at the Parkway [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[2]	12,615,887	12,721,014
Cumulative Unrealized Gain	[2]	2,369,577	2,790,208
Estimated Fair Value	[2]	14,985,464	15,511,222
Mortgage Revenue Bonds Held In Trust [Member] | Avistar at Wilcrest [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	5,197,106	5,235,915
Cumulative Unrealized Gain	[4]	748,346	1,084,347
Estimated Fair Value	[4]	5,945,452	6,320,262
Mortgage Revenue Bonds Held In Trust [Member] | Avistar at Wood Hollow [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]	39,461,504	39,756,184
Cumulative Unrealized Gain	[4]	6,913,829	8,703,609
Estimated Fair Value	[4]	46,375,333	48,459,793
Mortgage Revenue Bonds Held In Trust [Member] | Avistar in 09 [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	6,319,751	6,379,479
Cumulative Unrealized Gain	[3]	1,311,792	1,601,535
Estimated Fair Value	[3]	7,631,543	7,981,014
Mortgage Revenue Bonds Held In Trust [Member] | Avistar on the Boulevard [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	15,421,844	15,572,093
Cumulative Unrealized Gain	[3]	3,074,231	3,779,139
Estimated Fair Value	[3]	18,496,075	19,351,232
Mortgage Revenue Bonds Held In Trust [Member] | Avistar on the Hills [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[3]	5,010,813	5,058,171
Cumulative Unrealized Gain	[3]	1,101,075	1,292,513
Estimated Fair Value	[3]	6,111,888	6,350,684
Mortgage Revenue Bonds Held In Trust [Member] | Bruton Apartments [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	17,568,495	17,674,167
Cumulative Unrealized Gain	[1]	4,511,584	3,792,253
Estimated Fair Value	[1]	22,080,079	21,466,420
Mortgage Revenue Bonds Held In Trust [Member] | Concord at Gulfgate [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	18,655,305	18,796,773
Cumulative Unrealized Gain	[1]	4,168,584	4,888,537
Estimated Fair Value	[1]	22,823,889	23,685,310
Mortgage Revenue Bonds Held In Trust [Member] | Concord at Little York [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	13,068,923	13,168,029
Cumulative Unrealized Gain	[1]	3,027,488	3,543,909
Estimated Fair Value	[1]	16,096,411	16,711,938
Mortgage Revenue Bonds Held In Trust [Member] | Concord at Williamcrest [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	20,245,162	20,398,687
Cumulative Unrealized Gain	[1]	4,606,709	5,397,326
Estimated Fair Value	[1]	24,851,871	25,796,013
Mortgage Revenue Bonds Held In Trust [Member] | Crossing at 1415 [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	7,273,669	7,331,821
Cumulative Unrealized Gain	[1]	1,586,241	1,810,458
Estimated Fair Value	[1]	8,859,910	9,142,279
Mortgage Revenue Bonds Held In Trust [Member] | Decatur-Angle [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	22,124,707	22,270,729
Cumulative Unrealized Gain	[1]	5,058,303	5,600,721
Estimated Fair Value	[1]	27,183,010	27,871,450
Mortgage Revenue Bonds Held In Trust [Member] | Esperanza at Palo Alto [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	19,109,120	19,218,417
Cumulative Unrealized Gain	[1]	5,252,121	5,955,488
Estimated Fair Value	[1]	24,361,241	25,173,905
Mortgage Revenue Bonds Held In Trust [Member] | Heights at 515 [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	6,659,170	6,712,409
Cumulative Unrealized Gain	[1]	1,452,231	1,600,836
Estimated Fair Value	[1]	8,111,401	8,313,245
Mortgage Revenue Bonds Held In Trust [Member] | Heritage Square [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[2]	10,487,401	10,579,057
Cumulative Unrealized Gain	[2]	1,878,152	2,095,871
Estimated Fair Value	[2]	12,365,553	12,674,928
Mortgage Revenue Bonds Held In Trust [Member] | Oaks at Georgetown [Member] | Series A [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	12,054,029	12,135,392
Cumulative Unrealized Gain	[1]	2,173,762	2,597,201
Estimated Fair Value	[1]	14,227,791	14,732,593
Mortgage Revenue Bonds Held In Trust [Member] | Runnymede [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[5]	9,740,000	9,805,000
Cumulative Unrealized Gain	[5]	1,119	105,634
Estimated Fair Value	[5]	9,741,119	9,910,634
Mortgage Revenue Bonds Held In Trust [Member] | Southpark [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[5]	11,516,868	11,462,172
Cumulative Unrealized Gain	[5]	1,424,311	1,917,286
Estimated Fair Value	[5]	12,941,179	13,379,458
Mortgage Revenue Bonds Held In Trust [Member] | 15 West Apartments [Member] | WA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[1]	9,550,479	9,604,680
Cumulative Unrealized Gain	[1]	2,832,108	3,257,826
Estimated Fair Value	[1]	12,382,587	12,862,506
Mortgage Revenue Bonds Held In Trust [Member] | Rosewood Townhomes [Member] | Series A [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]		9,259,206
Cumulative Unrealized Gain	[4]		578,247
Estimated Fair Value	[4]		9,837,453
Mortgage Revenue Bonds Held In Trust [Member] | South Pointe Apartments [Member] | Series A [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances	[4]		21,551,600
Cumulative Unrealized Gain	[4]		1,345,919
Estimated Fair Value	[4]		22,897,519
Mortgage Revenue Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		14,572,900	24,472,905
Cumulative Unrealized Gain		1,239,284	1,490,936
Estimated Fair Value		15,812,184	25,963,841
Mortgage Revenue Bonds [Member] | Greens Property [Member] | Series B [Member] | NC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		921,935	925,607
Cumulative Unrealized Gain		62,330	107,347
Estimated Fair Value		984,265	1,032,954
Mortgage Revenue Bonds [Member] | Ohio Properties [Member] | Series B [Member] | OH [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		3,470,560	3,485,690
Cumulative Unrealized Gain			13,578
Estimated Fair Value		3,470,560	3,499,268
Mortgage Revenue Bonds [Member] | Avistar at the Crest [Member] | Series B [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		731,998	735,974
Cumulative Unrealized Gain		117,989	144,746
Estimated Fair Value		849,987	880,720
Mortgage Revenue Bonds [Member] | Avistar at the Oaks [Member] | Series B [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		535,927	538,723
Cumulative Unrealized Gain		85,705	100,668
Estimated Fair Value		621,632	639,391
Mortgage Revenue Bonds [Member] | Avistar at the Parkway [Member] | Series B [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		123,696	123,973
Cumulative Unrealized Gain		38,527	43,650
Estimated Fair Value		162,223	167,623
Mortgage Revenue Bonds [Member] | Avistar in 09 [Member] | Series B [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		442,092	444,398
Cumulative Unrealized Gain		70,699	83,042
Estimated Fair Value		512,791	527,440
Mortgage Revenue Bonds [Member] | Avistar on the Boulevard [Member] | Series B [Member] | TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		434,955	437,318
Cumulative Unrealized Gain		67,137	82,718
Estimated Fair Value		502,092	520,036
Mortgage Revenue Bonds [Member] | Solano Vista [Member] | Series A [Member] | CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		2,653,659	2,665,000
Cumulative Unrealized Gain		796,897	891,612
Estimated Fair Value		3,450,556	3,556,612
Mortgage Revenue Bonds [Member] | Provision Center 2014-1 [Member] | TN [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances		5,258,078	6,161,954
Estimated Fair Value		$ 5,258,078	6,161,954
Mortgage Revenue Bonds [Member] | Rosewood Townhomes [Member] | Series B [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances			469,781
Cumulative Unrealized Gain			2,549
Estimated Fair Value			472,330
Mortgage Revenue Bonds [Member] | South Pointe Apartments [Member] | Series B [Member] | SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances			1,099,487
Cumulative Unrealized Gain			5,967
Estimated Fair Value			1,105,454
Mortgage Revenue Bonds [Member] | Arby Road Apartments [Member] | Series A [Member] | NV [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost Adjusted for Paydowns and Allowances			7,385,000
Cumulative Unrealized Gain			15,059
Estimated Fair Value			$ 7,400,059

[1] MRBs owned by ATAX TEBS IV, LLC (M45 TEBS), Note 16

[2] MRBs owned by ATAX TEBS III, LLC (M33 TEBS), Note 16

[3] MRBs owned by ATAX TEBS II, LLC (M31 TEBS), Note 16

[4] MRBs held by Mizuho Capital Markets, LLC in a debt financing transaction, Note 16

[5] MRBs owned by ATAX TEBS I, LLC (M24 TEBS), Note 16

[6] MRB held by Morgan Stanley in a debt financing transaction, Note 16