SELECTED QUARTERLY FINANCIAL DATA (Tables)

12 Months Ended

Dec. 31, 2012

Selected Quarterly Financial Information [Abstract]

Schedule of Quarterly Financial Information

Selected quarterly financial data for the years ended December 31, 2012, 2011 and 2010 are presented in the following table:

	Three Months Ended,
Year ended December 31, 2012	December 31,			September 30,			June 30,			March 31,
Revenue	$	254,879,358		$	238,793,030		$	191,007,886		$	169,086,267
Cost of goods sold		(229,933,412	)		(213,536,628	)		(170,296,852	)		(150,451,275	)
Gross profit		24,945,946			25,256,402			20,711,034			18,634,992
Selling expenses		(786,331	)		(741,135	)		(740,988	)		(686,006	)
General and administrative expenses		(2,630,168	)		(2,059,027	)		(1,834,465	)		(2,097,834	)
Income from operations		21,529,447			22,456,240			18,135,581			15,851,152
Net income		15,793,687			17,226,638			13,446,666			11,475,012
Earnings per share
Basic	$	0.52		$	0.58		$	0.45		$	0.39
Diluted	$	0.52		$	0.58		$	0.45		$	0.38

	Three Months Ended
Year ended December 31, 2011	December 31,			September 30,			June 30,			March 31,
Revenue	$	177,579,159		$	155,570,657		$	167,012,527		$	136,931,096
Cost of goods sold		(157,877,953	)		(136,113,727	)		(147,365,064	)		(120,023,023	)
Gross profit		19,701,206			19,456,930			19,647,463			16,908,073
Selling expenses		(660,992	)		(633,584	)		(668,366	)		(523,036	)
General and administrative expenses		(2,239,462	)		(1,498,306	)		(1,339,062	)		(1,573,312	)
Income from operations		16,800,752			17,325,040			17,640,035			14,811,725
Net income		12,727,388			13,528,083			14,366,076			12,511,986
Earnings per share
Basic	$	0.43		$	0.45		$	0.48		$	0.42
Diluted	$	0.43		$	0.45		$	0.48		$	0.41

	Three Months Ended,
Year ended December 31, 2010	December 31,			September 30,			June 30,			March 31,
Revenue	$	135,471,182		$	96,337,451		$	75,502,350		$	63,220,702
Cost of goods sold		(114,812,441	)		(81,215,627	)		(61,002,044	)		(51,399,418	)
Gross profit		20,658,741			15,121,824			14,500,306			11,821,284
Selling expenses		(614,817	)		(422,209	)		(570,420	)		(450,877	)
General and administrative expenses		(1,776,457	)		(1,192,225	)		(1,484,893	)		(1,293,603	)
Income from operations		18,267,467			13,507,390			12,444,993			10,076,804
Net income		9,855,420			9,855,705			9,898,292			8,856,558
Earnings per share
Basic	$	0.34		$	0.34		$	0.35		$	0.35
Diluted	$	0.33		$	0.33		$	0.34		$	0.34