Commitments and Contingencies Fair Market Value Table (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-For-Sale Securities, Gross Unrealized Loss MTM	$ 17,516	$ 19,582
15 West Apartments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.25%
Long-term Purchase Commitment, Amount	9,900,000
Forward Bond Commitment, Purchase Date	Jul. 01, 2014
Villas at Plano Gateway [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Long-term Purchase Commitment, Amount	20,000,000
Forward Bond Commitment, Purchase Date	Dec. 01, 2014
Silver Moon [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Long-term Purchase Commitment, Amount	8,000,000
Forward Bond Commitment, Purchase Date	Jun. 01, 2013
Vantage at Harlingen [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-For-Sale Securities, Gross Unrealized Loss MTM	0	0
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Long-term Purchase Commitment, Amount	18,000,000
Forward Bond Commitment, Purchase Date	Aug. 01, 2013
Vantage at Judson [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-For-Sale Securities, Gross Unrealized Loss MTM	0	0
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Long-term Purchase Commitment, Amount	26,700,000
Forward Bond Commitment, Purchase Date	Dec. 01, 2012
Bond Purchase Commitment [Member] | 15 West Apartments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-For-Sale Securities, Gross Unrealized Loss MTM	744,660	809,178
Bond Purchase Commitment [Member] | Villas at Plano Gateway [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-For-Sale Securities, Gross Unrealized Loss MTM	1,005,800	1,133,400
Bond Purchase Commitment [Member] | Silver Moon [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-For-Sale Securities, Gross Unrealized Loss MTM	366,320	413,600
Bond Purchase Commitment [Member] | Vantage at Harlingen [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-For-Sale Securities, Gross Unrealized Loss MTM	1,278,900	1,433,700
Bond Purchase Commitment [Member] | Vantage at Judson [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-For-Sale Securities, Gross Unrealized Loss MTM	$ 1,808,508	$ 1,990,535