XML 40 R29.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Related Party (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2018
Related Party [Abstract] |
Schedule of Related Party Transactions [Table Text Block] | The related payments (receipts) with related parties for the three months ended March 31, 2018 and 2017 (in thousands) were as follows:
| Three months ended March 31,
| 2018 |  | 2017
Receipts for trailer sales | $ | — |  |  | $ | (12 | )
Payments for parts and services | 136 |  |  | 109 |
Terminal lease payments | 247 |  |  | 415 |
| $ | 383 |  |  | $ | 512 |

X
- Definition Related Party [Abstract] + References No definition available. + Details
Name: | htld_RelatedPartyAbstract
Namespace Prefix: | htld_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of related party transactions. Examples of related party transactions include, but are not limited to, transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners and (d) affiliates. + References No definition available. + Details
Name: | us-gaap_ScheduleOfRelatedPartyTransactionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration