Consolidated Statements Of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenues	$ 8,130,631	$ 7,686,999	$ 7,551,524
Cost of sales	6,925,178	6,539,987	6,513,662
Gross profit	1,205,453	1,147,012	1,037,862
Selling, general and administrative expenses	799,157	758,714	727,067
Restructuring expenses	2,306	1,577	1,438
Impairment loss on goodwill and identifiable intangible assets	907	57,819	2,428
Operating income	403,083	328,902	306,929
Net periodic pension (cost) income	2,743	1,652	1,529
Interest expense	(13,544)	(12,770)	(12,627)
Interest income	2,746	965	663
Income from continuing operations before income taxes	395,028	318,749	296,494
Income tax provision	109,106	90,699	111,199
Income from continuing operations	285,922	228,050	185,295
Loss from discontinued operation, net of income taxes	(2,345)	(857)	(3,142)
Net income including noncontrolling interests	283,577	227,193	182,153
Less: Net (income) loss attributable to noncontrolling interests	(46)	3	(218)
Net income attributable to EMCOR Group, Inc. (in US dollars)	$ 283,531	$ 227,196	$ 181,935
Basic earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	$ 4.92	$ 3.85	$ 3.05
From discontinued operation (in US dollars per share)	(0.04)	(0.01)	(0.05)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	4.88	3.84	3.00
Diluted earnings (loss) per common share:
From continuing operations attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	4.89	3.83	3.02
From discontinued operation (in US dollars per share)	(0.04)	(0.01)	(0.05)
Net income attributable to EMCOR Group, Inc. common stockholders (in US dollars per share)	4.85	3.82	2.97
Dividends declared per common share (in US dollars per share)	$ 0.32	$ 0.32	$ 0.32