Description of Business and Principles of Interim Statements - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
	Dec. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Description of Business [Line Items]
Impairment charge other-than-temporary impairments	$ 60,000	$ 0	$ 0	$ 60,000
Net realized loss on investments		(575,567)	$ 285,705
Allowance for doubtful accounts	0	0		0
Amount reclassified from other assets to long-term debt	1,700,000			1,700,000
Tenant Reimbursable Expenses
Description of Business [Line Items]
Accounts receivable included in other assets	831,000	53,000		831,000
Real Estate Operations
Description of Business [Line Items]
Accounts receivable included in other assets	1,300,000	4,000,000		1,300,000
ship And Event Receivables
Description of Business [Line Items]
Accounts receivable included in other assets	$ 253,000	$ 242,000		$ 253,000