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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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Accounting policies (Details Textual) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
Accounting policies (Details Textual) - USD ($)	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Feb. 29, 2016
Accounting Policies [Line Items]
Foreign Currency Transaction Gain (Loss), before Tax	$ (145,297)	$ 104,804	$ (41,742)	$ 169,951
Maximum [Member]
Accounting Policies [Line Items]
Percentage Of Bad Debts					1.00%
Aerex Industries Inc [Member]
Accounting Policies [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	51.00%		51.00%			51.00%
Certificates of Deposit [Member]
Accounting Policies [Line Items]
Cash Equivalents, at Carrying Value	$ 13,600,000		$ 13,600,000		$ 15,900,000
BELIZE
Accounting Policies [Line Items]
Deposits held in foreign bank	5,800,000		5,800,000
BAHAMAS
Accounting Policies [Line Items]
Deposits held in foreign bank	$ 6,300,000		$ 6,300,000