ORGANIZATION AND NATURE OF OPERATIONS (Details)	12 Months Ended
Dec. 31, 2020 Distributor
ORGANIZATION AND NATURE OF OPERATIONS
Number of independent distributors	80

Represents number of independent distributors for company's towing and recovery equipment.

No definition available.

Name:	mlr_NumberOfIndependentDistributor
Namespace Prefix:	mlr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration