Amount of deposits held in foreign banks, as stated in equivalent United States dollars.

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The percentage representing the bad debts.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage.

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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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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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Amount of cash restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

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Accounting policies - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Mar. 31, 2019
Foreign Currency Transaction Gain (Loss), before Tax [Abstract]
Foreign Currency Transaction Gain (Loss), before Tax	$ 41,977	$ 97,329	$ 54,012	$ 63,087
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Restricted Cash, Current	$ 1,610,471		$ 1,610,471		$ 0
Standby Letters of Credit [Member]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Long-term Line of Credit						$ 1,500,000
Maximum [Member]
Revenue Recognition [Abstract]
Percentage of Bad Debts			1.00%		1.00%
Aerex Industries Inc [Member]
Revenue Recognition [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	51.00%		51.00%
Certificates of Deposit [Member]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash Equivalents, at Carrying Value	$ 17,900,000		$ 17,900,000		$ 8,400,000
Restricted Cash, Current	1,600,000		1,600,000
Cash Collateral for Borrowed Securities	100,000		100,000
BAHAMAS
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Deposits held in foreign bank	$ 9,000,000		$ 9,000,000