Earnings Per Share - Summary of weighted average number of common shares used to compute basic and dilute earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net income attributable to MYR Group Inc.	$ 10,355	$ 7,957	$ 24,915	$ 20,436
Denominator:
Weighted average common shares outstanding (in shares)	16,614	16,492	16,576	16,423
Weighted average dilutive securities (in shares)	100	138	116	157
Weighted average common shares outstanding, diluted (in shares)	16,714	16,630	16,692	16,580
Income per common share attributable to MYR Group Inc.:
Basic (in dollars per share)	$ 0.62	$ 0.48	$ 1.50	$ 1.24
Diluted (in dollars per share)	$ 0.62	$ 0.48	$ 1.49	$ 1.23