Payments for parts and services

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

proceeds from sale of tractors

+ References

No definition available.

+ Details

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Namespace Prefix:	htld_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

proceeds from sale of trailers

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Amount of revenue from providing administrative services, including, but not limited to, accounting, tax, legal, regulatory filing, and share registration activities of managed funds and investment accounts of independent third parties and related and affiliated entities.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(k)(1))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 850

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph k

-Subparagraph 1

-Article 4

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Subparagraph a

-Article 5

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow for acquisition of machinery and equipment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 850

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

+ Details

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Balance Type:	debit
Period Type:	duration

- Details

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- Details

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- Details

Name:	us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis=htld_TerminalFacilitiesMember
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Related Party (Details) (USD $)	0 Months Ended	2 Months Ended	12 Months Ended
Related Party (Details) (USD $)	May 08, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Related Party Transaction [Line Items]
Due to Related Parties, Current		$ 1,300,000us-gaap_DueToRelatedPartiesCurrent	$ 100,000us-gaap_DueToRelatedPartiesCurrent	$ 1,300,000us-gaap_DueToRelatedPartiesCurrent
Operating Leases, Rent Expense			8,300,000us-gaap_LeaseAndRentalExpense	1,300,000us-gaap_LeaseAndRentalExpense
Payments to Acquire Property, Plant, and Equipment	2,800,000		204,973,000	135,195,000	66,811,000
Related Party Transaction, Expenses from Transactions with Related Party		7,208,000	49,882,000
Related Party [Member]
Related Party Transaction [Line Items]
Payments for tractor purchase		6,884,000	46,562,000
proceeds from sale of trailers		0	(103,000)
proceeds from sale of tractors		(2,138,000)	(15,564,000)
Payments for parts and services		1,058,000	5,906,000
Operating Leases, Rent Expense		930,000	6,842,000	930,000
Payments to Acquire Property, Plant, and Equipment	2,800,000	0
Administrative Services Revenue		(98,000)	(516,000)
Terminal Facilities [Member]
Related Party Transaction [Line Items]
Operating Leases, Rent Expense			4,200,000	700,000
Terminal Facilities [Member] \| Related Party [Member]
Related Party Transaction [Line Items]
Operating Leases, Rent Expense		572,000	3,930,000
Related Party Transaction, Expenses from Transactions with Related Party			$ 3,900,000	$ 600,000