SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Share-based payments (Details)	12 Months Ended
Dec. 31, 2017 item
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Number of trading sessions	20

Number of most recent trading sessions that the weighted average cost of ESPP are based on.

No definition available.

Name:	kgc_NumberOfTradingSessions
Namespace Prefix:	kgc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration