Income Taxes (Bonus Depreciation Impact) (Details)	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Percentage of bonus depreciation provision	50.00%
Percentage of new bonus depreciation provision	100.00%

Represents the percentage of bonus depreciation provision related to the Small Business Jobs Act of 2010.

No definition available.

Name:	eme_PercentageOfBonusDepreciationProvision
Namespace Prefix:	eme_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant