Quarterly report pursuant to Section 13 or 15(d)

Related Party Transactions (Details)

v3.19.1
Related Party Transactions (Details) - CHINA - Company's Joint Venture Partner - USD ($)
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
Related Party Transaction [Line Items]      
Payments for advance to affiliate $ 0 $ 2,000,000  
Payments for advance to affiliate by co-venturer $ 0 500,000  
Debt instrument, term 1 year    
Debt instrument, interest rate, stated percentage 3.00%    
Due from related parties $ 6,100,000   $ 6,000,000
Due to co-venturer from related party $ 1,500,000 $ 1,500,000