Condensed Consolidated Statements of Operations and Other Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating revenues:
Total operating revenues	$ 113,883	$ 88,969	$ 221,051	$ 176,129
Cost of sales	75,046	64,327	150,322	124,739
Gross Profit	38,837	24,642	70,729	51,390
Operating expenses:
Selling expense	(11,219)	(8,567)	(20,781)	(17,704)
General and administrative expense	(9,354)	(8,453)	(17,448)	(16,074)
Total Operating Expenses	(20,573)	(17,020)	(38,229)	(33,778)
Operating income	18,264	7,622	32,500	17,612
Non-operating income	353	709	628	1,808
Equity method income (loss)	(22)		(22)
Foreign currency transactions (losses) gains	(1,201)	(8,307)	2,085	1,666
Interest expense and deferred cost of financing	(5,757)	(5,361)	(11,344)	(10,411)
Income (loss) before taxes	11,637	(5,337)	23,847	10,675
Income tax (provision) benefit	(3,977)	1,467	(8,856)	(3,926)
Net income (loss)	7,660	(3,870)	14,991	6,749
(Income) loss attributable to non-controlling interest	(181)	212	(174)	284
Income (loss) attributable to parent	7,479	(3,658)	14,817	7,033
Comprehensive income:
Net income (loss)	7,660	(3,870)	14,991	6,749
Foreign currency translation adjustments	(2,052)	(6,139)	(282)	2,562
Total comprehensive income (loss)	5,608	(10,009)	14,709	9,311
Comprehensive (income) loss attributable to non-controlling interest	(181)	212	(174)	284
Total comprehensive income (loss) attributable to parent	$ 5,427	$ (9,797)	$ 14,535	$ 9,595
Basic income (loss) per share	$ 0.17	$ (0.10)	$ 0.35	$ 0.18
Diluted income (loss) per share	$ 0.17	$ (0.10)	$ 0.35	$ 0.17
Basic weighted average common shares outstanding	44,840,263	38,200,792	42,254,672	38,135,096
Diluted weighted average common shares outstanding	45,603,939	38,200,792	43,018,348	38,898,772
External Customers [Member]
Operating revenues:
Total operating revenues	$ 112,259	$ 87,785	$ 217,067	$ 173,992
Related Parties [Member]
Operating revenues:
Total operating revenues	$ 1,624	$ 1,184	$ 3,984	$ 2,137