Subsequent Events Level 1 (Notes)	12 Months Ended
Dec. 31, 2013
Subsequent Events [Abstract]
Subsequent Events [Text Block]	SUBSEQUENT EVENTS On January 16, 2014, the Company closed on $44,000,000 of refinancing debt for Berkshires of Columbia. The mortgage has a variable rate of 2.43% above the 1-month LIBOR and will mature on February 1, 2024. Proceeds from the new mortgage were used to pay off three existing loans on the Berkshire of Columbia property totaling $32,254,893. On January 16, 2014, the Board authorized the general partner of the Operating Partnership to make a special distribution of $20,000,000 from proceeds of the supplemental loan on Seasons and the refinancing of Berkshires of Columbia to the common general and noncontrolling interest partners in Operating Partnership, which was paid on January 17, 2014. Also on January 16, 2014, the Board declared a common dividend of $0.339924 per share on the Company's Class B common stock in respect to the special distribution to the common general partner. Concurrently with the Operating Partnership distributions, the common dividend was paid from the special distribution proceeds of the common general partner on January 17, 2014. On January 21, 2014, the Company closed on a $90,000,000 line of credit (the "Credit Facility") with an unaffiliated lender. The Credit Facility will be used to facilitate property acquisitions and to fund the development activities of the Company. On the same day, the Company borrowed $30,000,000 on the Credit Facility. On January 22, 2014, the Company executed a joint venture limited liability company agreement with an unrelated entity for the development of Aura Prestonwood, a 322-unit multifamily apartment project in Dallas, Texas. The Company's ownership percentage in the project will be 95% when fully funded. Total capital committed to the venture is $12,643,500. Simultaneously with the execution of the limited liability company agreement, the joint venture acquired the land where the multifamily apartment project will be built. The cost of the land was $7,302,960 and consideration of $1,000,000 was paid at closing for the option to acquire the abutting land parcel at a future time. On January 27, 2014, the Company executed a purchase and sale agreement for the sale of Laurel Woods in Austin, Texas. The sale price of the property is $13,200,000. The closing is currently anticipated to take place on April 30, 2014. On March 20, 2014, the Company, through its subsidiaries, BIR Pavilion, L.L.C. and BIR Eon, L.L.C., completed the acquisitions of Pavilion Townplace, a 236-unit multifamily apartment community located in Dallas, Texas and Eon at Lindbergh, a 352-unit multifamily apartment community located in Atlanta, Georgia, respectively. The seller was an unaffiliated third party. The purchase prices for Pavilion Townplace and Eon at Lindbergh were $56,000,000 and $64,000,000, respectively, and were subject to normal operating prorations and adjustments as provided for in the purchase and sale agreements. On March 24, 2014, the Company executed a purchase and sale agreement for the sale of Berkshire on Brompton in Houston, Texas. The sale price of the property is $38,500,000. The closing is currently anticipated to take place on May 29, 2014. On March 31, 2014, the Company through its joint venture partnership for the Walnut Creek Project, paid off the outstanding land loan balance of $4,828,495 with available funds contributed to the joint venture partnership. The loan was assumed on November 1, 2013 as part of the acquisition of the land for the Walnut Creek project.

SUBSEQUENT EVENTS

On January 16, 2014, the Company closed on $44,000,000 of refinancing debt for Berkshires of Columbia. The mortgage has a variable rate of 2.43% above the 1-month LIBOR and will mature on February 1, 2024. Proceeds from the new mortgage were used to pay off three existing loans on the Berkshire of Columbia property totaling $32,254,893.

On January 16, 2014, the Board authorized the general partner of the Operating Partnership to make a special distribution of $20,000,000 from proceeds of the supplemental loan on Seasons and the refinancing of Berkshires of Columbia to the common general and noncontrolling interest partners in Operating Partnership, which was paid on January 17, 2014. Also on January 16, 2014, the Board declared a common dividend of $0.339924 per share on the Company's Class B common stock in respect to the special distribution to the common general partner. Concurrently with the Operating Partnership distributions, the common dividend was paid from the special distribution proceeds of the common general partner on January 17, 2014.

On January 21, 2014, the Company closed on a $90,000,000 line of credit (the "Credit Facility") with an unaffiliated lender. The Credit Facility will be used to facilitate property acquisitions and to fund the development activities of the Company. On the same day, the Company borrowed $30,000,000 on the Credit Facility.

On January 22, 2014, the Company executed a joint venture limited liability company agreement with an unrelated entity for the development of Aura Prestonwood, a 322-unit multifamily apartment project in Dallas, Texas. The Company's ownership percentage in the project will be 95% when fully funded. Total capital committed to the venture is $12,643,500. Simultaneously with the execution of the limited liability company agreement, the joint venture acquired the land where the multifamily apartment project will be built. The cost of the land was $7,302,960 and consideration of $1,000,000 was paid at closing for the option to acquire the abutting land parcel at a future time.

On January 27, 2014, the Company executed a purchase and sale agreement for the sale of Laurel Woods in Austin, Texas. The sale price of the property is $13,200,000. The closing is currently anticipated to take place on April 30, 2014.

On March 20, 2014, the Company, through its subsidiaries, BIR Pavilion, L.L.C. and BIR Eon, L.L.C., completed the acquisitions of Pavilion Townplace, a 236-unit multifamily apartment community located in Dallas, Texas and Eon at Lindbergh, a 352-unit multifamily apartment community located in Atlanta, Georgia, respectively. The seller was an unaffiliated third party. The purchase prices for Pavilion Townplace and Eon at Lindbergh were $56,000,000 and $64,000,000, respectively, and were subject to normal operating prorations and adjustments as provided for in the purchase and sale agreements.

On March 24, 2014, the Company executed a purchase and sale agreement for the sale of Berkshire on Brompton in Houston, Texas. The sale price of the property is $38,500,000. The closing is currently anticipated to take place on May 29, 2014.

On March 31, 2014, the Company through its joint venture partnership for the Walnut Creek Project, paid off the outstanding land loan balance of $4,828,495 with available funds contributed to the joint venture partnership. The loan was assumed on November 1, 2013 as part of the acquisition of the land for the Walnut Creek project.