XML 14 R3.htm IDEA: XBRL DOCUMENT
v3.21.1

Unaudited Condensed Consolidated Balance Sheets (Parenthetical) | Mar. 31, 2021 $ / shares shares | Dec. 31, 2020 $ / shares shares
--- | --- | ---
Class A Common Stock |  |
Common stock, par value (in dollars per share) | $ / shares | $ 1 | $ 1
Common stock, shares outstanding (in shares) | shares | 5,583,099 | 5,489,615
Class B Common Stock |  |
Common stock, par value (in dollars per share) | $ / shares | $ 1 | $ 1
Common stock, shares outstanding (in shares) | shares | 1,566,643 | 1,568,210
Common stock, convertible conversion ratio | 1 | 1

X
- Definition Common Stock, Convertible Conversion Ratio + References No definition available. + Details
Name: | nacco_CommonStockConvertibleConversionRatio
Namespace Prefix: | nacco_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Face amount or stated value per share of common stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |