XML 58 R41.htm IDEA: XBRL DOCUMENT
v3.20.4

STOCK-BASED COMPENSATION PLANS - Narrative (Details) - Stock Options - 2016 Stock Incentive Plan - shares | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | --- | ---
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of shares available for granting options | 800,000 | 800,000 | 800,000
Number of shares of common stock are available for issuance | 800,000 |  |

X
- Definition Number of share of common stock are available for issuance under a share-based compensation plan. + References No definition available. + Details
Name: | mlr_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForIssuance
Namespace Prefix: | mlr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=mlr_StockIncentivePlan2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |