Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) Loan Facility Tenant shares	Dec. 31, 2014 USD ($) Property Derivative	Dec. 31, 2013 USD ($) Property	Feb. 18, 2016 a	Jan. 01, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 a	Dec. 31, 2015 Property	Dec. 31, 2015 State	Dec. 31, 2015 ft²	Dec. 31, 2015 Billboard	Dec. 31, 2015 Derivative	Jan. 31, 2013 Property	Apr. 25, 2011 shares
Description of Business [Line Items]
Number of owned and managed commercial real estate properties | Property								40
Number of states in which entity operates | State									10
Commercial real estate properties | Property								32
Self developed multi-tenant properties | Property								8
Gross leasable space							160			1,700,000
Land portfolio | a							10,500
Number of billboards leased for property | Billboard											21
Cash and cash equivalents maximum original maturity period	90 days
Restricted Cash		$ 4,440,098				$ 14,060,523
Cash held in reserve for property taxes and insurance escrows						12,500,000
Cash held in escrow related to land transaction			$ 14,000			133,000
Number of income properties acquired | Property		4	9					4					2
Reserve for future interest payment	$ 781,000
Impairment charge other-than-temporary impairments	60,000	$ 0
Derivatives outstanding | Derivative		0										0
Allowance for doubtful accounts		$ 0				0
Subsurface interest net cost basis						0
Depreciation and amortization of property plant and equipment	5,212,897	3,490,485	$ 2,974,587
Interest paid, capitalized	$ 0	11,000	8,000
Facilities operated by company | Facility	2
Golf course and clubhouse facility membership period	12 months
Award plan, number of common stock that may be issued | shares														500,000
2001 plan expiry date	2011-04
Number of new option shares issued after April 2011 | shares	0
Stock options vesting period	5 years
Stock options expiration period	10 years
Reserves for uncertain income tax positions						0
Income property portfolio, interest rate	43.00%
Number of tenants | Tenant	0
Amount reclassified to land, timber, and development costs		14,900,000
Reclassifications to the purchase price allocations, increase in intangible assets		3,000,000
Reclassifications to the purchase price allocations, decrease in properties, land, buildings, and improvements		(2,300,000)
Reclassifications to the purchase price allocations, increase in accrued and other liabilities		670,000
Increase in revenues and the direct costs of revenues		$ 537,000	$ 232,000
Number of income properties acquired during prior year finalized | Property		3
Subsequent Event [Member]
Description of Business [Line Items]
Gross leasable space | a				0.37
Unamortized debt issuance costs					$ 1,700,000
Sales Revenue, Net [Member]
Description of Business [Line Items]
Income portfolio, rent percentage	10.00%	10.00%	10.00%
2010 Plan [Member]
Description of Business [Line Items]
Award plan, number of common stock that may be issued | shares	450,000
Number of additional shares authorized | shares	240,000
Share Based awards, maximum subscription per participant | shares	50,000
2010 plan award termination description	The 2010 Plan will terminate on the tenth anniversary of the date that it was adopted by the Board, and no awards will be granted under the plan after that date.
Intangible Assets [Member]
Description of Business [Line Items]
Depreciation and amortization of property plant and equipment	$ 3,500,000	$ 2,700,000	$ 2,300,000
Tenant Reimbursable Expenses
Description of Business [Line Items]
Accounts receivable included in other assets		412,000				831,000
Lease Income
Description of Business [Line Items]
Accounts receivable included in other assets		1,300,000				1,800,000
Real Estate Operations
Description of Business [Line Items]
Accounts receivable included in other assets		0				1,300,000
ship And Event Receivables
Description of Business [Line Items]
Accounts receivable included in other assets		$ 261,000				253,000
Atlanta, GA [Member]
Description of Business [Line Items]
Number of commercial mortgage loan investments | Loan	4
Katy, Texas [Member] | Reserve for Tenant Improvements [Member]
Description of Business [Line Items]
Restricted Cash						$ 609,000