XML 59 R26.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Significant Accounting Policies Segment Information (Details) | Dec. 31, 2012 locations segments divisions
--- | ---
Segment Reporting Information |
Number of Regional Operating Divisions | 11
Numer of Segments | 1
Number of Office Locations | 10

X
- Definition Number of Office Locations + References No definition available. + Details
Name: | htld_NumberOfOfficeLocations
Namespace Prefix: | htld_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of Regional Operating Divisions + References No definition available. + Details
Name: | htld_NumberOfRegionalOperatingDivisions
Namespace Prefix: | htld_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Numer of Segments + References No definition available. + Details
Name: | htld_NumerOfSegments
Namespace Prefix: | htld_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration