XML 41 R29.htm IDEA: XBRL DOCUMENT v3.19.2
Fair value measurement - Assets and liabilities measured on a recurring basis (Details) - Recurring - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
Assets, Fair Value Disclosure [Abstract]    
Cash and cash equivalents $ 187,035 $ 237,342
Total assets 187,035 237,342
Liabilities, Fair Value Disclosure [Abstract]    
Total liabilities 3,251 1,375
Related party    
Liabilities, Fair Value Disclosure [Abstract]    
Derivative financial instruments 3,251 803
Debt    
Liabilities, Fair Value Disclosure [Abstract]    
Derivative financial instruments   572
Fair value hierarchy Level 1    
Assets, Fair Value Disclosure [Abstract]    
Cash and cash equivalents 187,035 237,342
Total assets 187,035 237,342
Level 3    
Liabilities, Fair Value Disclosure [Abstract]    
Total liabilities 3,251 1,375
Level 3 | Related party    
Liabilities, Fair Value Disclosure [Abstract]    
Derivative financial instruments $ 3,251 803
Level 3 | Debt    
Liabilities, Fair Value Disclosure [Abstract]    
Derivative financial instruments   $ 572