XML 89 R71.htm IDEA: XBRL DOCUMENT
v3.21.1

Business Segments - Additional Information (Detail) | 12 Months Ended
--- | ---
Mar. 31, 2021 Location Facility Terminal Plant Sector Segment
Segment Reporting [Abstract] |
Number of sectors | Sector | 2
Number of reportable business segments | Segment | 4
Cement plant locations | Location | 8
Slag grinding facility | Facility | 1
Cement distribution terminals | Terminal | 29
Gypsum wallboard plants | 5
Readymix concrete batch plants | 26
Aggregates processing plants | 3
Proportionate consolidation of share of joint venture revenues and operating earnings | 50.00%

X
- Definition Aggregates processing plants. + References No definition available. + Details
Name: | exp_AggregatesProcessingPlants
Namespace Prefix: | exp_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition Cement distribution terminals. + References No definition available. + Details
Name: | exp_CementDistributionTerminals
Namespace Prefix: | exp_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition Cement plant locations. + References No definition available. + Details
Name: | exp_CementPlantLocations
Namespace Prefix: | exp_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition Gypsum wallboard plants. + References No definition available. + Details
Name: | exp_GypsumWallboardPlants
Namespace Prefix: | exp_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of sectors. + References No definition available. + Details
Name: | exp_NumberOfSectors
Namespace Prefix: | exp_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Readymix plants. + References No definition available. + Details
Name: | exp_ReadymixPlants
Namespace Prefix: | exp_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition Segment reporting information proportionate consolidation of joint ventures revenues and operating earnings. + References No definition available. + Details
Name: | exp_SegmentReportingInformationProportionateConsolidationOfJointVenturesRevenuesAndOperatingEarnings
Namespace Prefix: | exp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Slag grinding facility. + References No definition available. + Details
Name: | exp_SlagGrindingFacility
Namespace Prefix: | exp_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8672-108599 + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_SegmentReportingAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration