REVENUE (Detail Textuals) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018
Revenue from Contract with Customer [Abstract]
Contract liability balances related to extended service contracts	$ 708	$ 154

Represents the amount of contract liability balances related to extended service contracts.

No definition available.

Name:	mlr_ServiceContractsContractLiability
Namespace Prefix:	mlr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant