UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect Adjustment	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Retained Earnings Cumulative Effect Adjustment	MYR Group Inc. Stockholders' Equity	MYR Group Inc. Stockholders' Equity Cumulative Effect Adjustment	Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to adopt ASC 326	$ 324,464		$ 0	$ 165	$ 148,276	$ (193)	$ 174,736		$ 322,984		$ 1,480
Balance, beginning of period at Dec. 31, 2018	324,464		0	$ 165	148,276	(193)	174,736		322,984		1,480
Balance, beginning of period (in shares) at Dec. 31, 2018				16,565
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	6,620						7,353		7,353		(733)
Adjustment to adopt ASC 326	331,474		0	$ 177	148,938	(270)	181,882		330,727		747
Stock issued under compensation plans, net	282				282				282
Stock issued under compensation plans, net (in shares)				68
Stock-based compensation expense	951				951				951
Shares repurchased	(778)				(571)		(207)		(778)
Shares repurchased (in shares)				(23)
Other comprehensive income (loss)	(77)					(77)			(77)
Stock issued - other	12			$ 12					12
Balance, end of period at Mar. 31, 2019	331,474		0	$ 177	148,938	(270)	181,882		330,727		747
Balance, end of period (in shares) at Mar. 31, 2019				16,610
Balance, beginning of period at Dec. 31, 2018	324,464		0	$ 165	148,276	(193)	174,736		322,984		1,480
Balance, beginning of period (in shares) at Dec. 31, 2018				16,565
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	23,439
Adjustment to adopt ASC 326	350,572		0	$ 166	151,350	(392)	199,444		350,568		4
Other comprehensive income (loss)	(199)
Balance, end of period at Sep. 30, 2019	350,572		0	$ 166	151,350	(392)	199,444		350,568		4
Balance, end of period (in shares) at Sep. 30, 2019				16,647
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to adopt ASC 326	331,474		0	$ 177	148,938	(270)	181,882		330,727		747
Balance, beginning of period at Mar. 31, 2019	331,474		0	$ 177	148,938	(270)	181,882		330,727		747
Balance, beginning of period (in shares) at Mar. 31, 2019				16,610
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	6,358						7,207		7,207		(849)
Adjustment to adopt ASC 326	338,937		0	$ 166	150,177	(393)	189,089		339,039		(102)
Stock issued under compensation plans, net	2			$ 1	1				2
Stock issued under compensation plans, net (in shares)				33
Stock-based compensation expense	1,202				1,202				1,202
Other comprehensive income (loss)	(123)					(123)			(123)
Stock issued - other	24			$ (12)	36				24
Stock issued - other (in shares)				1
Balance, end of period at Jun. 30, 2019	338,937		0	$ 166	150,177	(393)	189,089		339,039		(102)
Balance, end of period (in shares) at Jun. 30, 2019				16,644
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to adopt ASC 326	338,937		0	$ 166	150,177	(393)	189,089		339,039		(102)
Net income (loss)	10,461						10,355		10,355		106
Adjustment to adopt ASC 326	350,572		0	$ 166	151,350	(392)	199,444		350,568		4
Stock issued under compensation plans, net	41				41				41
Stock-based compensation expense	1,108				1,108				1,108
Stock-based compensation expense (in shares)				2
Other comprehensive income (loss)	1					1			1
Stock issued - other	24				24				24
Stock issued - other (in shares)				1
Balance, end of period at Sep. 30, 2019	350,572		0	$ 166	151,350	(392)	199,444		350,568		4
Balance, end of period (in shares) at Sep. 30, 2019				16,647
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to adopt ASC 326	350,572		0	$ 166	151,350	(392)	199,444		350,568		4
Adjustment to adopt ASC 326	364,475	$ (268)	0	166	152,532	(446)	212,219	$ (268)	364,471	$ (268)	4
Balance, beginning of period at Dec. 31, 2019	364,475	(268)	0	$ 166	152,532	(446)	212,219	(268)	364,471	(268)	4
Balance, beginning of period (in shares) at Dec. 31, 2019				16,649
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	9,932						9,932		9,932
Adjustment to adopt ASC 326	374,986	(268)	0	$ 166	153,477	(359)	221,698	(268)	374,982	(268)	4
Stock issued under compensation plans, net	82				82				82
Stock issued under compensation plans, net (in shares)				55
Stock-based compensation expense	1,080				1,080				1,080
Shares repurchased	(426)				(241)		(185)		(426)
Shares repurchased (in shares)				(20)
Other comprehensive income (loss)	87					87			87
Stock issued - other	24				24				24
Stock issued - other (in shares)				1
Balance, end of period at Mar. 31, 2020	$ 374,986		0	$ 166	153,477	(359)	221,698		374,982		4
Balance, end of period (in shares) at Mar. 31, 2020				16,685
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Balance, beginning of period at Dec. 31, 2019	$ 364,475	(268)	0	$ 166	152,532	(446)	212,219	(268)	364,471	(268)	4
Balance, beginning of period (in shares) at Dec. 31, 2019				16,649
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	40,609
Adjustment to adopt ASC 326	408,604	$ (268)	0	$ 167	156,461	(403)	252,375	$ (268)	408,600	$ (268)	4
Other comprehensive income (loss)	43
Balance, end of period at Sep. 30, 2020	$ 408,604		0	$ 167	156,461	(403)	252,375		408,600		4
Balance, end of period (in shares) at Sep. 30, 2020				16,719
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Adjustment to adopt ASC 326	$ 374,986		0	$ 166	153,477	(359)	221,698		374,982		4
Balance, beginning of period at Mar. 31, 2020	374,986		0	$ 166	153,477	(359)	221,698		374,982		4
Balance, beginning of period (in shares) at Mar. 31, 2020				16,685
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	13,385						13,385		13,385
Adjustment to adopt ASC 326	389,450		0	$ 167	154,594	(398)	235,083		389,446		4
Stock issued under compensation plans, net	1			$ 1					1
Stock issued under compensation plans, net (in shares)				23
Stock-based compensation expense	1,093				1,093				1,093
Other comprehensive income (loss)	(39)					(39)			(39)
Stock issued - other	24				24				24
Stock issued - other (in shares)				1
Balance, end of period at Jun. 30, 2020	389,450		0	$ 167	154,594	(398)	235,083		389,446		4
Balance, end of period (in shares) at Jun. 30, 2020				16,709
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to adopt ASC 326	389,450		0	$ 167	154,594	(398)	235,083		389,446		4
Net income (loss)	17,292						17,292		17,292
Adjustment to adopt ASC 326	408,604		0	$ 167	156,461	(403)	252,375		408,600		4
Stock issued under compensation plans, net	224				224				224
Stock issued under compensation plans, net (in shares)				10
Stock-based compensation expense	1,631				1,631				1,631
Other comprehensive income (loss)	(5)					(5)			(5)
Stock issued - other	12				12				12
Balance, end of period at Sep. 30, 2020	408,604		0	$ 167	156,461	(403)	252,375		408,600		4
Balance, end of period (in shares) at Sep. 30, 2020				16,719
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to adopt ASC 326	$ 408,604		$ 0	$ 167	$ 156,461	$ (403)	$ 252,375		$ 408,600		$ 4