Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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- Definition

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

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Intangible assets (Details Textual) - USD ($)		12 Months Ended
Intangible assets (Details Textual) - USD ($)	Feb. 11, 2016	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets		$ 1,340,000	$ 1,363,850
Aerex Industries Inc [Member]
Finite-Lived Intangible Assets [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	51.00%	51.00%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 5,900,000
Aerex Industries Inc [Member] \| Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years
Aerex Industries Inc [Member] \| Certification Marks [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	3 years
Aerex Industries Inc [Member] \| Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	1 year
Aerex Industries Inc [Member] \| Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	4 years
Trade Names [Member] \| Aerex Industries Inc [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	15 years