v2.4.1.9
Summary of Significant Accounting Policies Realized Gain (Loss) on Short-Term Investments (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Cash, Cash Equivalents, and Short-term Investments [Abstract]      
Available-for-sale Securities, Gross Realized Gains $ 48us-gaap_AvailableForSaleSecuritiesGrossRealizedGains $ 166us-gaap_AvailableForSaleSecuritiesGrossRealizedGains $ 14us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Available-for-sale Securities, Gross Realized Losses (681)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses (678)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses (249)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses
Available-for-sale Securities, Gross Realized Gain (Loss) $ (633)us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet $ (512)us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet $ (235)us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet