Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Numerator
Income from continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars)	$ 33,204	$ 43,302
Loss from discontinued operation, net of income taxes (in US dollars)	(355)	(2,041)
Net income attributable to EMCOR Group, Inc. (in US dollars)	$ 32,849	$ 41,261
Denominator
Weighted average shares outstanding used to compute basic earnings (loss) per common share (in shares)	63,058,911	67,188,577
Effect of dilutive securities-Share-based awards (in shares)	552,100	812,628
Shares used to compute diluted earnings (loss) per common share (in shares)	63,611,011	68,001,205
Basic earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 0.53	$ 0.64
From discontinued operation (in US dollars per share)	$ (0.01)	$ (0.03)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 0.52	$ 0.61
Diluted earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 0.52	$ 0.64
From discontinued operation (in US dollars per share)	$ 0.00	$ (0.03)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 0.52	$ 0.61
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive stock options excluded from calculation of diluted earnings per share (in shares)	1,000	0