Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Schedule of Weighted Average Assumptions for Restricted Stock Units) (Details)

v2.4.1.9
Stock-Based Compensation (Schedule of Weighted Average Assumptions for Restricted Stock Units) (Details) (Restricted Stock Units (RSUs) [Member], USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Restricted Stock Units (RSUs) [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period 3 years 9 months 29 days 3 years 10 months 2 days 3 years 10 months 10 days
Expected dividend yield 1.33%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
1.58%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
1.77%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
Estimated average fair value per restricted stock unit granted $ 38.98us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
$ 26.67us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
$ 23.29us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember