UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net cash provided by operating activities	$ 66,949,790	$ 28,429,789
Cash flows from investing activities:
Purchase of time deposits		(163,426,937)
Proceeds from maturity of time deposits		119,741,660
Purchase of and deposits for property, plant and equipment	(11,471,899)	(64,469,960)
Refund of deposit from an equipment supplier		60,054,417
Government grant related to the industrial project for metric tons biological composite materials		6,953,816
Cash disposed for sales of a subsidiary	(3,217)
Net cash used in investing activities	(11,475,116)	(41,147,004)
Cash flows from financing activities:
Proceeds from bank borrowings	357,291,327	251,134,403
Repayment of bank borrowings	(281,123,795)	(347,339,779)
Proceeds from interest-free advances from related parties	289,298
Net cash provided by (used in) financing activities	76,456,830	(96,205,376)
Effect of foreign currency exchange rate changes on cash, cash equivalents, and restricted cash	7,289,967	10,101,313
Net increase (decrease) in cash, cash equivalents, and restricted cash	139,221,471	(98,821,278)
Cash, cash equivalents, and restricted cash at beginning of period	366,991,840	320,091,665
Cash, cash equivalents, and restricted cash at end of period	506,213,311	221,270,387
Supplemental disclosure of cash flow information:
Interest paid, net of capitalized interest	13,316,939	11,062,464
Income taxes paid	2,276,847	7,064,571
Non-cash investing and financing activities:
Accrual for purchase of property, plant and equipment	$ 1,181,670	$ 196,911