Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Data (Unaudited)
Revenues	$ 571,075	$ 583,214	$ 448,776	$ 468,094	$ 446,345	$ 399,537	$ 339,676	$ 345,611	$ 2,071,159	$ 1,531,169	$ 1,403,317
Gross profit	68,922	59,197	43,163	42,876	47,391	45,286	38,630	35,753	214,158	167,060	125,004
Net income attributable to MYR Group	$ 12,775	$ 10,355	$ 7,207	$ 7,353	$ 10,651	$ 7,957	$ 6,835	$ 5,644	$ 37,690	$ 31,087	$ 21,154
Basic earnings per share attributable to MYR Group (in dollars per share)	$ 0.77	$ 0.62	$ 0.43	$ 0.45	$ 0.65	$ 0.48	$ 0.42	$ 0.35	$ 2.27	$ 1.89	$ 1.30
Diluted earnings per share attributable to MYR Group (in dollars per share)	$ 0.76	$ 0.62	$ 0.43	$ 0.44	$ 0.64	$ 0.48	$ 0.41	$ 0.34	$ 2.26	$ 1.87	$ 1.28