Shareholders’ Equity - Follow-on public offerings (Details) $ / shares in Units, $ in Thousands	Jan. 22, 2018 USD ($) $ / shares shares
Follow-on public offering
Shareholders' equity
Share price, ADS (in dollars per share) | $ / shares	$ 101.00
Share price (in dollars per share) | $ / shares	$ 7.77
Number of new stock issued during the period, American Depository Shares.	7,425,750
Shares issued (in shares)	96,534,750
Net proceeds | $	$ 757,587
Over-Allotment Option
Shareholders' equity
Number of new stock issued during the period, American Depository Shares.	495,050
Shares issued (in shares)	6,435,650