Trade Accounts and Bills Receivable, Net (Details Textual) - USD ($)	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Trade Accounts and Bills Receivable, Net (Textual)
Retention receivable	$ 1,706,061	$ 1,119,490
Retention period, descrption	Retention receivables are interest-free and recoverable at the end of the retention period of three to five years.