Description of Business and Principles of Interim Statements - Cash and Restricted Cash (Detail)	9 Months Ended
	Sep. 30, 2016 USD ($) item	Dec. 31, 2015 USD ($) item	Sep. 30, 2015 property	Dec. 31, 2013 item
Description of Business [Line Items]
Restricted Cash	$ 6,643,732	$ 14,060,523
Cash and cash equivalents maximum original maturity period	90 days
Number of income properties acquired | property			3
Escrow Deposit to be Reinvested Through Like-Kind Exchange Structure [Member]
Description of Business [Line Items]
Restricted Cash	$ 3,100,000
Number of income properties to be reinvested | item	1
Restricted Cash Reserve for Property Taxes and Insurance Escrows for Property Financing [Member]
Description of Business [Line Items]
Restricted Cash	$ 393,000
Number of separate escrow accounts | item	2
Restricted Cash, Escrow Deposit Related to Land Transactions [Member]
Description of Business [Line Items]
Restricted Cash	$ 432,000
Number of separate escrow accounts | item	3
Number of separate land transactions | item	3
Number of closed land transactions | item		2		1
Restricted Cash, Consolidated Variable Interest Entity [Member]
Description of Business [Line Items]
Restricted Cash	$ 28,000
Winter Park, Florida | Restricted Cash, Escrow for Tenant Improvements [Member]
Description of Business [Line Items]
Restricted Cash	2,100,000
Katy, Texas [Member] | Restricted Cash, Escrow for Tenant Improvements [Member]
Description of Business [Line Items]
Restricted Cash	$ 647,000