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
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Cash, Cash Equivalents, and Short-term Investments [Abstract] |  |  |
Available-for-sale Securities, Gross Realized Gains | $ 48 us-gaap_AvailableForSaleSecuritiesGrossRealizedGains | $ 166 us-gaap_AvailableForSaleSecuritiesGrossRealizedGains | $ 14 us-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

X
- Definition This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_CashCashEquivalentsAndShortTermInvestmentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration