Earnings per share (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Numerator:
Net income attributable to the Company	$ 644,362	$ (630,510)	$ 1,151,261	$ (596,767)
Denominator:
Weighted-average shares outstanding	13,582,106	13,582,106	13,582,106	13,582,106
Effect of dilutive securities
Weighted-average shares diluted	13,582,106	13,582,106	13,582,106	13,582,106
-Basic	$ 0.05	$ (0.05)	$ 0.08	$ (0.04)
-Diluted	$ 0.05	$ (0.05)	$ 0.08	$ (0.04)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation	727,500	637,500	727,500	637,500
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation	680,000		680,000
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation	47,500		47,500