Summary of Significant Accounting Policies (Details)	6 Months Ended
Jun. 30, 2011
Summary of Significant Accounting Policies
Number of business segments	3
Number of towns to which water service is provided	3

Name:

ede_NumberOfTownsToWhichEntityProvidesWaterService

Namespace Prefix:

ede

Data Type:

xbrli:integerItemType

Balance Type:

na

Period Type:

duration