Contracts in Process (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Contracts in Process [Line Items]
Costs and estimated earnings on uncompleted contracts	$ 1,978,981	$ 2,194,695
Less: Billings to date	1,929,640	2,167,066
Net asset position for contracts in process	$ 49,341	$ 27,629

Represents the net costs and estimated earnings in excess of billings on uncompleted contracts accounted for under the percentage-of-completion method.

No definition available.

Name:	myrg_NetCostsAndEstimatedEarningsInExcessOfBillings
Namespace Prefix:	myrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant