Condensed Consolidated Statements Of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenues	$ 1,886,691	$ 1,923,174	$ 5,674,360	$ 5,601,560
Cost of sales	1,591,621	1,655,130	4,838,449	4,835,667
Gross profit	295,070	268,044	835,911	765,893
Selling, general and administrative expenses	188,565	181,441	552,903	530,654
Restructuring expenses	46	539	954	1,271
Operating income	106,459	86,064	282,054	233,968
Interest expense	(3,324)	(3,479)	(9,464)	(8,973)
Interest income	277	161	607	518
Income from continuing operations before income taxes	103,412	82,746	273,197	225,513
Income tax provision	38,608	30,783	98,473	82,663
Income from continuing operations	64,804	51,963	174,724	142,850
Loss from discontinued operation, net of income taxes	(207)	(406)	(729)	(1,584)
Net income including noncontrolling interests	64,597	51,557	173,995	141,266
Less: Net income attributable to noncontrolling interests	0	(26)	0	(7)
Net income attributable to EMCOR Group, Inc. (in US dollars)	$ 64,597	$ 51,531	$ 173,995	$ 141,259
Basic earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 1.10	$ 0.85	$ 2.94	$ 2.35
From discontinued operation (in US dollars per share)	0.00	(0.01)	(0.01)	(0.03)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	1.10	0.84	2.93	2.32
Diluted earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	1.09	0.85	2.93	2.33
From discontinued operation (in US dollars per share)	0.00	(0.01)	(0.01)	(0.03)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	1.09	0.84	2.92	2.30
Dividends declared per common share (in US dollars per share)	$ 0.08	$ 0.08	$ 0.24	$ 0.24