XML 110 R116.htm IDEA: XBRL DOCUMENT v3.20.1
Employee benefits - Narrative (Details)
12 Months Ended
Dec. 31, 2019
USD ($)
benefit_plan
Employee Benefits [Abstract]  
Number of defined benefit plans 3
Number of defined benefit plans that are fully insured 1
Estimate of contributions expected to be paid to plan for next annual reporting period | $ $ 49,596