XML 34 R22.htm IDEA: XBRL DOCUMENT
v3.20.4

Schedule II Valuation of Qualifying Accounts and Reserves | 12 Months Ended
--- | ---
Dec. 31, 2020
Schedule II Valuation and Qualifying Accounts and Reserves [Abstract] |
SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] |
SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (In Thousands, Except Per Share Data)
|  |  |  | Column C |  |  |  |
Column A |  | Column B |  | Charges To |  | Column D |  | Column E
|  | Balance At |  | Cost |  |  |  |  |  | Balance
|  | Beginning |  | And |  | Other |  |  |  | At End
Description |  | of Period |  | Expense |  | Accounts |  | Deductions |  | of Period
Allowance for doubtful accounts: |  |  |  |  |  |  |  |  |  |
Year ended December 31, 2020 |  | $ | 1,100 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 1,100 |
Year ended December 31, 2019 |  | 900 |  |  | 200 |  |  | — |  |  | — |  |  | 1,100 |
Year ended December 31, 2018 |  | 1,475 |  |  | — |  |  | — |  |  | 575 |  |  | 900 |
See accompanying Report of Independent Registered Public Accounting Firm.

X
- Definition Schedule II Valuation and Qualifying Accounts and Reserves [Abstract] + References No definition available. + Details
Name: | htld_ScheduleIiValuationAndQualifyingAccountsAndReservesAbstract
Namespace Prefix: | htld_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 09 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
Name: | srt_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock
Namespace Prefix: | srt_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration