Consolidated Statements of Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Consolidated Statements Of Comprehensive Income
Net income	$ 4,052,479	$ 5,850,998
Other comprehensive gain (loss) -
Foreign currency translation	614,741	(89,556)
Change in net prior service credit and actuarial gains, net of income tax expense	87,461	284,145
Total other comprehensive income	702,202	194,589
Comprehensive income	$ 4,754,681	$ 6,045,587