v2.4.1.9
Investments (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Schedule Of Trading Securities And Other Trading Assets [Line Items]    
Certificates of deposit and money market funds due within one year $ 335,975dva_CertificatesOfDepositMoneyMarketFundsAndUnitedStatesGovernmentSecurities $ 5,601dva_CertificatesOfDepositMoneyMarketFundsAndUnitedStatesGovernmentSecurities
Investments in mutual funds and common stock 28,123dva_MutualFundInvestmentsAtFairValue 19,421dva_MutualFundInvestmentsAtFairValue
Total investment 364,098us-gaap_MarketableSecurities 25,022us-gaap_MarketableSecurities
Short-term investments 337,399us-gaap_MarketableSecuritiesCurrent 6,801us-gaap_MarketableSecuritiesCurrent
Long-term investments 26,699us-gaap_MarketableSecuritiesNoncurrent 18,221us-gaap_MarketableSecuritiesNoncurrent
Held to maturity    
Schedule Of Trading Securities And Other Trading Assets [Line Items]    
Certificates of deposit and money market funds due within one year 335,975dva_CertificatesOfDepositMoneyMarketFundsAndUnitedStatesGovernmentSecurities
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_HeldtomaturitySecuritiesMember
5,601dva_CertificatesOfDepositMoneyMarketFundsAndUnitedStatesGovernmentSecurities
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_HeldtomaturitySecuritiesMember
Total investment 335,975us-gaap_MarketableSecurities
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_HeldtomaturitySecuritiesMember
5,601us-gaap_MarketableSecurities
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_HeldtomaturitySecuritiesMember
Short-term investments 335,975us-gaap_MarketableSecuritiesCurrent
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_HeldtomaturitySecuritiesMember
5,601us-gaap_MarketableSecuritiesCurrent
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_HeldtomaturitySecuritiesMember
Available for sale    
Schedule Of Trading Securities And Other Trading Assets [Line Items]    
Investments in mutual funds and common stock 28,123dva_MutualFundInvestmentsAtFairValue
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_AvailableforsaleSecuritiesMember
19,421dva_MutualFundInvestmentsAtFairValue
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_AvailableforsaleSecuritiesMember
Total investment 28,123us-gaap_MarketableSecurities
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_AvailableforsaleSecuritiesMember
19,421us-gaap_MarketableSecurities
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_AvailableforsaleSecuritiesMember
Short-term investments 1,424us-gaap_MarketableSecuritiesCurrent
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_AvailableforsaleSecuritiesMember
1,200us-gaap_MarketableSecuritiesCurrent
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_AvailableforsaleSecuritiesMember
Long-term investments $ 26,699us-gaap_MarketableSecuritiesNoncurrent
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_AvailableforsaleSecuritiesMember
$ 18,221us-gaap_MarketableSecuritiesNoncurrent
/ us-gaap_InformationByCategoryOfDebtSecurityAxis
= us-gaap_AvailableforsaleSecuritiesMember