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           Income Taxes (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        3 Months Ended | |
|---|---|---|
| 
           Mar. 31, 2015 
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           Mar. 31, 2014 
         | 
      |
| Current Taxes: | ||
| Federal | $ 8,093us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations | $ 12,882us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations | 
| State, net of federal benefit | 804us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations | 1,499us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations | 
| Total | $ 8,897us-gaap_IncomeTaxExpenseBenefit | $ 14,381us-gaap_IncomeTaxExpenseBenefit | 
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- Details 
          
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- Definition 
          Amount of current and deferred federal income tax expense (benefit) attributable to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of state and local current and deferred income tax expense (benefit) attributable to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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