Property, Plant and Equipment, Net (Details) (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Property Plant And Equipment [Line Items]
Property, plant and equipment	$ 70,493,220		$ 69,139,347
Less: accumulated depreciation and amortization	(26,980,554)		(23,699,987)
Total property, plant and equipment, net	43,512,666		45,439,360
Depreciation - property, plant and equipment	3,280,567	3,284,259
Buildings [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	6,913,305		6,773,312
Shop equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	20,108,558		19,483,024
Office equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	4,323,285		4,243,396
Motor Vehicles [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	1,490,510		1,460,327
Car park [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	20,813		20,392
Leasehold improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment	27,711,305		27,150,156
Construction In Progress [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	$ 9,925,444		$ 10,008,740