SCHEDULE OF SHARE-BASED PAYMENT AWARD, VALUATION ASSUMPTIONS (Details)	3 Months Ended	9 Months Ended
Sep. 30, 2012 Y	Jun. 30, 2011 Y	Sep. 30, 2012 Y	Sep. 30, 2011 Y
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	0.60%	1.00%	0.90%	2.30%
Expected life (in years)	5.0	5.0	5.0	5.0
WESCO expected volatility	50.00%	48.00%	50.00%	49.00%
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	850	15,156	257,932	399,330
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	2,400	0	74,724	53,852
Performance-based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	0	0	46,804	0

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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