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Subsequent Events (Details)	Jul. 11, 2011
Subsequent Event
Restricted Stock Shares Authorized	906,886

X

- Definition

Restricted Stock Shares Authorized

+ Details

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Namespace Prefix:	htld
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration