Annual report pursuant to Section 13 and 15(d)

Stock-based and Long-Term Compensation - Schedule of Restricted Stock Activity (Details)

v2.4.1.9
Stock-based and Long-Term Compensation - Schedule of Restricted Stock Activity (Details) (Restricted Stock, Common Class A, USD $)
12 Months Ended
Dec. 31, 2014
Restricted Stock | Common Class A
 
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]  
Outstanding at January 1, 2014 66,677us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Granted (in shares) 17,639us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Vested (in shares) (21,866)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Canceled (in shares) (900)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Outstanding at December 31, 2014 61,550us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]  
Beginning of Period, Weighted Average Grant Date Fair Value (in USD per share) $ 48.36us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Granted (in USD per share) $ 63.99us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Vested (in USD per share) $ 48.81us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Canceled (in USD per share) $ 50.47us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Ending of Period, Weighted Average Grant Date Fair Value (in USD per share) $ 52.64us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember