Leases - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Operating Leases [Line Items]
Operating lease revenues collected	$ 461,800	$ 449,225	$ 1,007,324	$ 985,775
Operating percentage rents	205,645	193,700	238,583	219,200	465,406
Rents and other receivables for unbilled percentage rents	$ 238,583		$ 238,583		$ 465,406
Maximum [Member]
Operating Leases [Line Items]
Original lease terms of properties			20 years
Minimum [Member]
Operating Leases [Line Items]
Original lease terms of properties			5 years