Income Properties - Additional Information (Detail) (USD $)	0 Months Ended		12 Months Ended			0 Months Ended					12 Months Ended
	Jan. 31, 2013 Buildings	Jan. 03, 2013 Property	Dec. 31, 2013 Property sqft	Dec. 31, 2012 Property	Dec. 31, 2011	Jan. 23, 2013 Glendale [Member] acre	Jul. 25, 2013 Seattle [Member] sqft Lease	Sep. 13, 2013 Germantown [Member] sqft Lease	Jan. 31, 2013 Building [Member] sqft	Jan. 23, 2013 Building [Member] Glendale [Member] sqft	Dec. 31, 2013 Intangible Assets [Member]	Dec. 31, 2012 Intangible Assets [Member]	Dec. 31, 2013 Land [Member]	Dec. 31, 2012 Land [Member]	Dec. 31, 2013 Golf Buildings and Improvements [Member]	Dec. 31, 2012 Golf Buildings and Improvements [Member]
Business Acquisition [Line Items]
Number of income properties acquired	2	4	9	8
Total acquisition cost of property			$ 39,500,000	$ 25,900,000
Purchase price allocated to amortizable intangible assets			2,920,739	1,478,688	130,070						2,900,000	1,500,000
Purchase price allocated to land													13,200,000	14,700,000
Purchase price allocated to buildings and improvements															23,400,000	9,700,000
Weighted average amortization allocated to intangible assets, period			10 years 6 months
Acquisition costs in connection with acquisition of two income properties			90,000
Number of income properties on which company expensed			2
Remaining term of lease	8 years	15 years				10 years	13 years	10 years 4 months 24 days
Aggregate purchase price	$ 14,600,000	$ 8,000,000	$ 37,868,099	$ 24,916,936	$ 3,197,276	$ 5,000,000	$ 6,600,000	$ 5,000,000
Area of real property acquired			740,000			3.62				34,512
Area of property acquired							16,280	25,600	133,000
Number of lease extension options							6	3
Period of lease extension							5 years	5 years