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Income Taxes (Details) (USD $) | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Income Taxes [Abstract] |  |  |
PortionOfTaxBenefitRecordedPositionsMoreLikelyThanNotToBeSustained | 50.00%htld_Portionoftaxbenefitrecordedpositionsmorelikelythannottobesustained |  |
Income Tax Uncertainties [Abstract] |  |  |
Unrecognized Tax Benefits that Would Impact Effective Tax Rate | $ 8,000,000 us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate | $ 8,600,000 us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate |
Unrecognized Tax Benefits, Period Increase (Decrease) | (800,000)us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease | (2,300,000)us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease |
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued | 5,700,000 us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued | 6,700,000 us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued |
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense | 1,000,000 us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense | 700,000 us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense | 600,000 us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound | (700,000)us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleEstimatedRangeOfChangeLowerBound |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound | (1,700,000)us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleEstimatedRangeOfChangeUpperBound |  |
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] |  |  |
Balance beginning of period | 13,432,000 us-gaap_UnrecognizedTaxBenefits | 15,723,000 us-gaap_UnrecognizedTaxBenefits |
Additions based on tax positions related to current year | 983,000 us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions | 843,000 us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions |
Additions for tax positions of prior years | 277,000 us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions | 616,000 us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions |
Reductions for tax positions of prior years | 0 us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions | (300,000)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions |
Reductions due to lapse of applicable statute of limitations | (2,060,000)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations | (1,984,000)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations |
Settlements | 0 us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities | (1,466,000)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities |
Balance end of period | 12,632,000 us-gaap_UnrecognizedTaxBenefits | 13,432,000 us-gaap_UnrecognizedTaxBenefits | 15,723,000 us-gaap_UnrecognizedTaxBenefits
Valuation Allowance [Abstract] |  |  |
Valuation Allowance, Amount | $ 0 us-gaap_DeferredTaxAssetsValuationAllowance | $ 0 us-gaap_DeferredTaxAssetsValuationAllowance |

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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319 + Details
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- Definition Amount of (increase) decrease reasonably possible in the estimated lower bound of the unrecognized tax benefit for a tax position taken or expected to be taken. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
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- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
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- Definition Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
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