Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Insurance coverage	$ 250,000
Cash and cash equivalents in excess of insured limit	2,216,000
Asset impairment loss	0	$ 0
Amortization expense for finance costs	$ 26,562	28,439
Average life of membership	12 years
Rental pool distributions	$ 3,100,000	3,200,000
Income tax expense recorded	0
Uncertain income tax positions	$ 0	$ 0
Year under income tax examination		2017	2016	2015
Federal income tax returns period	3 years
Selling and Marketing Expense [Member]
Significant Accounting Policies [Line Items]
Advertising costs	$ 404,000	$ 356,000