v2.4.1.9
Income Taxes - Summary of Federal Statutory Rate and Provision for Income (Detail) (USD $)
3 Months Ended 12 Months Ended
Dec. 27, 2014
Dec. 28, 2013
Dec. 27, 2014
Dec. 28, 2013
Income Tax Disclosure [Abstract]        
Income tax at federal rate     $ 348,642us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate $ 456,885us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate
State tax, net of Federal effect     43,334us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes 56,788us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes
Permanent Differences:        
Meals & Entertainment     21,722us-gaap_IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment 20,792us-gaap_IncomeTaxReconciliationNondeductibleExpenseMealsAndEntertainment
Officers Life Insurance     1,337us-gaap_IncomeTaxReconciliationNondeductibleExpenseLifeInsurance 1,337us-gaap_IncomeTaxReconciliationNondeductibleExpenseLifeInsurance
Charitable Contribution C/F       (646)us-gaap_IncomeTaxReconciliationNondeductibleExpenseCharitableContributions
Domestic Production Activities Deduction     (22,017)us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities (25,954)us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities
Total Permanent Differences     1,042us-gaap_IncomeTaxReconciliationNondeductibleExpense (4,471)us-gaap_IncomeTaxReconciliationNondeductibleExpense
NOL Deduction       (27,192)dvly_EffectiveIncomeTaxRateReconciliationNetOperatingLossAdjustments
Total Tax Credits     (27,214)us-gaap_IncomeTaxReconciliationTaxCredits (20,068)us-gaap_IncomeTaxReconciliationTaxCredits
Prior Period over/under accrual     8,475us-gaap_IncomeTaxReconciliationPriorYearIncomeTaxes 66,612us-gaap_IncomeTaxReconciliationPriorYearIncomeTaxes
Rounding     (1)us-gaap_IncomeTaxReconciliationOtherReconcilingItems (8)us-gaap_IncomeTaxReconciliationOtherReconcilingItems
Provision for income taxes $ 176,737us-gaap_IncomeTaxExpenseBenefit $ 327,762us-gaap_IncomeTaxExpenseBenefit $ 374,278us-gaap_IncomeTaxExpenseBenefit $ 528,546us-gaap_IncomeTaxExpenseBenefit
Income tax at federal rate, percentage     34.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate 34.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
State tax, net of Federal effect, percentage     4.23%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes 4.23%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes
Permanent Differences:        
Meals & Entertainment, percentage     2.12%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseMealsAndEntertainment 1.55%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseMealsAndEntertainment
Officers Life Insurance, percentage     0.13%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseLifeInsurance 0.10%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseLifeInsurance
Charitable Contribution C/F, percentage     0.00%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseCharitableContributions (0.05%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseCharitableContributions
Domestic Production Activities Deduction, percentage     (2.15%)us-gaap_EffectiveIncomeTaxRateReconciliationDeductionsQualifiedProductionActivities (1.94%)us-gaap_EffectiveIncomeTaxRateReconciliationDeductionsQualifiedProductionActivities
Total Permanent Differences, percentage     0.10%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense (0.34%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense
NOL Deduction, percentage     0.00%dvly_EffectiveIncomeTaxRateReconciliationNetOperatingLossAdjustment (2.02%)dvly_EffectiveIncomeTaxRateReconciliationNetOperatingLossAdjustment
Total Tax Credits, percentage     (2.65%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits (1.49%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits
Prior Period over/under accrual, percentage     0.82%us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes 4.95%us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes
Rounding, percentage     0.00%us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent 0.00%us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent
Total Provision, percentage     36.50%us-gaap_EffectiveIncomeTaxRateContinuingOperations 39.33%us-gaap_EffectiveIncomeTaxRateContinuingOperations