Prepayments to equipment and construction suppliers (Schedule of Total Prepayments to Equipment Suppliers) (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Long-term Purchase Commitment [Line Items]
Total Prepayments to equipment and construction suppliers	$ 524,297,914	$ 530,636,319
Hailezi [Member]
Long-term Purchase Commitment [Line Items]
Total Prepayments to equipment and construction suppliers	511,758,267	502,087,116
Green River[Member]
Long-term Purchase Commitment [Line Items]
Total Prepayments to equipment and construction suppliers		15,778,057
Beijin Construction [Member]
Long-term Purchase Commitment [Line Items]
Total Prepayments to equipment and construction suppliers	7,006,972	6,867,269
Sichuan Construction [Member]
Long-term Purchase Commitment [Line Items]
Total Prepayments to equipment and construction suppliers	5,312,422	5,539,471
Others [Member]
Long-term Purchase Commitment [Line Items]
Total Prepayments to equipment and construction suppliers	$ 220,253	$ 364,406