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
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net income attributable to MYR Group Inc.	$ 7,353	$ 5,644
Denominator:
Weighted average common shares outstanding (in shares)	16,514	16,321
Weighted average dilutive securities (in shares)	144	199
Weighted average common shares outstanding, diluted (in shares)	16,658	16,520
Income per common share attributable to MYR Group Inc.:
Basic (in dollars per share)	$ 0.45	$ 0.35
Diluted (in dollars per share)	$ 0.44	$ 0.34