CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
NET REVENUE	$ 900,726,958	$ 853,766,541	$ 637,093,439
Cost of sales	(814,327,740)	(764,218,167)	(561,379,767)
GROSS PROFIT	86,399,218	89,548,374	75,713,672
Selling expenses	(3,020,600)	(2,954,460)	(2,485,978)
General and administrative expenses	(8,073,172)	(8,621,494)	(6,650,142)
Income from operations	75,305,446	77,972,420	66,577,552
Other income (expenses):
Interest income	660,326	547,679	522,722
Interest expenses	0	0	(143,779)
Foreign exchange differences	(1,636)	109,638	234,763
Gain (Loss) on extinguishment of warrant liabilities	(8,369)	73,291	88,777
Change in fair value of warrants	(106,536)	(124,000)	3,062,575
Other income (expenses)	35,136	93,819	114,623
Total other income (expenses)	578,921	700,427	3,879,681
Income before income taxes	75,884,367	78,672,847	70,457,233
Provision for income taxes	(19,724,917)	(20,730,844)	(17,323,700)
NET INCOME	56,159,450	57,942,003	53,133,533
OTHER COMPREHENSIVE INCOME:
Foreign currency translation adjustments	9,538,569	659,754	9,152,577
COMPREHENSIVE INCOME	$ 65,698,019	$ 58,601,757	$ 62,286,110
Net income per share
Basic	$ 1.88	$ 1.94	$ 1.78
Diluted	$ 1.87	$ 1.93	$ 1.77
Weighted average number of shares outstanding
Basic	29,858,880	29,815,943	29,816,871
Diluted	29,996,833	29,965,811	30,076,130