Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator
Net income attributable to EMCOR Group, Inc. (in US dollars)	$ 383,532	$ 132,943	$ 325,140
Denominator
Weighted average shares outstanding used to compute basic earnings per common share (in shares)	54,068,982	55,196,173	56,208,280
Effect of dilutive securities-Share-based awards (in shares)	278,552	225,098	311,001
Shares used to compute diluted earnings per common share (in shares)	54,347,534	55,421,271	56,519,281
Basic earnings per common share (in US dollars per share)	$ 7.09	$ 2.41	$ 5.78
Diluted earnings per common share (in US dollars per share)	$ 7.06	$ 2.40	$ 5.75