XML 18 R28.htm IDEA: XBRL DOCUMENT v2.4.1.9
SHARE-BASED COMPENSATION (Details) (USD $)
9 Months Ended 12 Months Ended 0 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Jun. 30, 2014
Feb. 18, 2010
Stock options and warrants        
Number of stock award plans prior to the adoption of 2010 plan       2hdy_NumberOfShareBasedCompensationPlanAvailablePriorToAdoptionOf2010Plan
Weighted Average Exercise Price        
Outstanding at the end of the period (in dollars per share)   $ 10.40us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice    
Stock options        
Options granted to employees and directors        
Number of options granted (in shares) 101,106us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
7,421us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Compensation expense recognized $ 526,000us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
$ 537,000us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Weighted average fair value of options outstanding (in dollars per share) $ 7.13hdy_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageFairValue
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
$ 7.36hdy_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageFairValue
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Significant assumptions used to compute the fair market values        
Risk-free interest rate, low end of range (as a percent) 0.05%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
0.08%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Risk-free interest rate, high end of range (as a percent) 0.12%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
0.90%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Dividend yield (as a percent) 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Volatility factor, low end of range (as a percent) 65.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
74.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Volatility factor, high end of range (as a percent) 216.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
95.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Expected life 6 months      
Options        
Outstanding at the beginning of the period (in shares) 1,441,727us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Granted (in shares) 101,106us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
7,421us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
   
Forfeited (in shares) (474,353)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Expired (in shares) (211,776)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Outstanding at the end of the period (in shares) 856,704us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
1,100,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
1,441,727us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
 
Options exercisable at end of period (in shares) 614,146us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Weighted Average Exercise Price        
Outstanding at the beginning of the period (in dollars per share) $ 8.76us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Granted (in dollars per share) $ 3.25us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Forfeited (in dollars per share) $ 3.82us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Expired (in dollars per share) $ 10.81us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Outstanding at the end of the period (in dollars per share) $ 10.34us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
$ 11.28us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
$ 8.76us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
 
Options exercisable at end of period (in dollars per share) $ 12.94us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Aggregate intrinsic value        
Outstanding at the end of the period     8,327us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
 
Options exercisable at period end 7us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Weighted average remaining contractual term (years)        
Outstanding at the end of the period 2 years 11 months 1 day   3 years 1 month 21 days  
Options exercisable at period end 2 years 6 months 22 days      
Options outstanding and exercisable        
Outstanding number of shares 856,704us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Exercisable number of shares 614,146us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Nonvested Share-based Compensation Arrangements, Additional Disclosure        
Unrecognized compensation costs $ 300,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
     
Stock options | Minimum        
Significant assumptions used to compute the fair market values        
Expected life   6 months    
Nonvested Share-based Compensation Arrangements, Additional Disclosure        
Amortization period 2 years      
Stock options | Maximum        
Significant assumptions used to compute the fair market values        
Expected life   3 years 3 months    
Nonvested Share-based Compensation Arrangements, Additional Disclosure        
Amortization period 3 years      
Stock options | Exercise price range $1.92 - $4.00 | Remaining Life, 1 year        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 1.92us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Exercise Price, high end of the range (in dollars per share) $ 4.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Outstanding number of shares 121,067us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Remaining life 1 year      
Exercisable number of shares 121,067us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Stock options | Exercise price range $1.92 - $4.00 | Remaining life, 4 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 1.92us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFourMember
     
Exercise Price, high end of the range (in dollars per share) $ 4.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFourMember
     
Outstanding number of shares 232,706us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFourMember
     
Remaining life 4 years      
Exercisable number of shares 78,856us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFourMember
     
Stock options | Exercise price range $1.92 - $4.00 | Remaining life, 3 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 1.92us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeThreeMember
     
Exercise Price, high end of the range (in dollars per share) $ 4.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeThreeMember
     
Outstanding number of shares 95,764us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeThreeMember
     
Remaining life 3 years      
Exercisable number of shares 38,171us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars1.92To4.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeThreeMember
     
Stock options | Exercise price range $4.01 - $10.00 | Remaining Life, 1 year        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 4.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Exercise Price, high end of the range (in dollars per share) $ 10.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Outstanding number of shares 49,749us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Remaining life 1 year      
Exercisable number of shares 49,749us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Stock options | Exercise price range $4.01 - $10.00 | Remaining life, 3 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 4.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeThreeMember
     
Exercise Price, high end of the range (in dollars per share) $ 10.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeThreeMember
     
Outstanding number of shares 16,437us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeThreeMember
     
Remaining life 3 years      
Exercisable number of shares 13,031us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeThreeMember
     
Stock options | Exercise price range $4.01 - $10.00 | Remaining life, 2 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 4.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Exercise Price, high end of the range (in dollars per share) $ 10.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Outstanding number of shares 111,251us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Remaining life 2 years      
Exercisable number of shares 84,167us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Stock options | Exercise price range $4.01 - $10.00 | Remaining life, 5 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 4.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFiveMember
     
Exercise Price, high end of the range (in dollars per share) $ 10.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFiveMember
     
Outstanding number of shares 30,500us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFiveMember
     
Remaining life 5 years      
Exercisable number of shares 30,500us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars4.01To10.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFiveMember
     
Stock options | Exercise price range $10.01 - $20.00 | Remaining Life, 1 year        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 10.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Exercise Price, high end of the range (in dollars per share) $ 20.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Outstanding number of shares 1,250us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Remaining life 1 year      
Exercisable number of shares 1,250us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Stock options | Exercise price range $10.01 - $20.00 | Remaining life, 2 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 10.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Exercise Price, high end of the range (in dollars per share) $ 20.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Outstanding number of shares 1,875us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Remaining life 2 years      
Exercisable number of shares 1,250us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Stock options | Exercise price range $10.01 - $20.00 | Remaining life, 5 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 10.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFiveMember
     
Exercise Price, high end of the range (in dollars per share) $ 20.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFiveMember
     
Outstanding number of shares 28,750us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFiveMember
     
Remaining life 5 years      
Exercisable number of shares 28,750us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars10.01To20.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeFiveMember
     
Stock options | Exercise price range $20.01 - $30.00 | Remaining Life, 1 year        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 20.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Exercise Price, high end of the range (in dollars per share) $ 30.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Outstanding number of shares 16,667us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Remaining life 1 year      
Exercisable number of shares 16,667us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Stock options | Exercise price range $20.01 - $30.00 | Remaining life, 2 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 20.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Exercise Price, high end of the range (in dollars per share) $ 30.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Outstanding number of shares 1,250us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Remaining life 2 years      
Exercisable number of shares 1,250us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeTwoMember
     
Stock options | Exercise price range $20.01 - $30.00 | Remaining life, 6 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 20.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Exercise Price, high end of the range (in dollars per share) $ 30.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Outstanding number of shares 31,625us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Remaining life 6 years      
Exercisable number of shares 31,625us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars20.01To30.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Stock options | Exercise price range $30.01 - $40.00 | Remaining Life, 1 year        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 30.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars30.01To40.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Exercise Price, high end of the range (in dollars per share) $ 40.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars30.01To40.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Outstanding number of shares 79,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars30.01To40.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Remaining life 1 year      
Exercisable number of shares 79,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars30.01To40.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Stock options | Exercise price range $30.01 - $40.00 | Remaining life, 6 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 30.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars30.01To40.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Exercise Price, high end of the range (in dollars per share) $ 40.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars30.01To40.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Outstanding number of shares 27,563us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars30.01To40.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Remaining life 6 years      
Exercisable number of shares 27,563us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars30.01To40.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Stock options | Exercise price range $40.01 - $50.00 | Remaining Life, 1 year        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 40.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars40.01To50.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Exercise Price, high end of the range (in dollars per share) $ 50.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars40.01To50.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Outstanding number of shares 6,250us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars40.01To50.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Remaining life 1 year      
Exercisable number of shares 6,250us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars40.01To50.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeOneMember
     
Stock options | Exercise price range $40.01 - $50.00 | Remaining life, 6 years        
Options outstanding and exercisable        
Exercise Price, low end of the range (in dollars per share) $ 40.01us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars40.01To50.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Exercise Price, high end of the range (in dollars per share) $ 50.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars40.01To50.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Outstanding number of shares 5,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars40.01To50.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
Remaining life 6 years      
Exercisable number of shares 5,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis
= hdy_ExercisePriceRangeDollars40.01To50.00Member
/ hdy_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByRemainingContractualLifeAxis
= hdy_RemainingContractualLifeSixMember
     
2010 Plan | Stock options        
Stock options and warrants        
Period within which shares of common stock, options or restricted stock can be granted under the 2010 plan       10 years
Number of shares issuable under the plan 1,250,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_PlanNameAxis
= hdy_EquityIncentivePlan2010Member
     
Number of shares remaining available for issuance 369,753us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_AwardTypeAxis
= hdy_EmployeeAndDirectorsStockOptionsMember
/ us-gaap_PlanNameAxis
= hdy_EquityIncentivePlan2010Member