Contract Assets and Liabilities - Contracts in process (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Contract Assets and Liabilities
Costs and estimated earnings on uncompleted contracts	$ 3,455,512	$ 3,532,886
Less: billings to date	3,426,094	3,509,472
Net asset position for contracts in process	$ 29,418	$ 23,414

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