Contracts in Process (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Contracts in Process [Line Items]
Costs and estimated earnings on uncompleted contracts	$ 2,437,192	$ 1,978,981
Less: Billings to date	2,359,321	1,929,640
Net asset position for contracts in process	$ 77,871	$ 49,341

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