XML 114 R87.htm IDEA: XBRL DOCUMENT v3.10.0.1
STOCK-BASED COMPENSATION - SCHEDULE OF SHARE-BASED PAYMENT AWARD, PERFORMANCE-BASED AWARDS, VALUATION ASSUMPTIONS (Details) - $ / shares
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 2.50% 1.90% 1.20%
Correlation   0.00% 0.00%
Performance Shares [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Grant date share price $ 62.80 $ 71.67 $ 42.44
WESCO expected volatility   0.00% 0.00%
Risk-free interest rate   0.00% 0.00%