v2.4.0.8
Fair Value Measurements Fair Value Heirarchy (Details) (USD $)
In Thousands, unless otherwise specified
6 Months Ended
Jun. 30, 2013
Jun. 30, 2013
Fair Value, Inputs, Level 1 [Member]
Dec. 31, 2012
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2012
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
Fair Value, Inputs, Level 3 [Member]
Dec. 31, 2012
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
Fair value [Member]
Dec. 31, 2012
Fair value [Member]
Jun. 30, 2013
Corporate Bonds
Fair Value, Inputs, Level 1 [Member]
Dec. 31, 2012
Corporate Bonds
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
Corporate Bonds
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2012
Corporate Bonds
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
Corporate Bonds
Fair Value, Inputs, Level 3 [Member]
Dec. 31, 2012
Corporate Bonds
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
Corporate Bonds
Fair value [Member]
Dec. 31, 2012
Corporate Bonds
Fair value [Member]
Jun. 30, 2013
Commercial Paper
Fair Value, Inputs, Level 1 [Member]
Dec. 31, 2012
Commercial Paper
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
Commercial Paper
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2012
Commercial Paper
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
Commercial Paper
Fair Value, Inputs, Level 3 [Member]
Dec. 31, 2012
Commercial Paper
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
Commercial Paper
Fair value [Member]
Dec. 31, 2012
Commercial Paper
Fair value [Member]
Jun. 30, 2013
Negotiable Certificates of Deposit
Fair Value, Inputs, Level 1 [Member]
Dec. 31, 2012
Negotiable Certificates of Deposit
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
Negotiable Certificates of Deposit
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2012
Negotiable Certificates of Deposit
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
Negotiable Certificates of Deposit
Fair Value, Inputs, Level 3 [Member]
Dec. 31, 2012
Negotiable Certificates of Deposit
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
Negotiable Certificates of Deposit
Fair value [Member]
Dec. 31, 2012
Negotiable Certificates of Deposit
Fair value [Member]
Jun. 30, 2013
US Treasury Notes
Fair Value, Inputs, Level 1 [Member]
Dec. 31, 2012
US Treasury Notes
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
US Treasury Notes
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2012
US Treasury Notes
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
US Treasury Notes
Fair Value, Inputs, Level 3 [Member]
Dec. 31, 2012
US Treasury Notes
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
US Treasury Notes
Fair value [Member]
Dec. 31, 2012
US Treasury Notes
Fair value [Member]
Jun. 30, 2013
Agencies Securities
Fair Value, Inputs, Level 1 [Member]
Dec. 31, 2012
Agencies Securities
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
Agencies Securities
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2012
Agencies Securities
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
Agencies Securities
Fair Value, Inputs, Level 3 [Member]
Dec. 31, 2012
Agencies Securities
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
Agencies Securities
Fair value [Member]
Dec. 31, 2012
Agencies Securities
Fair value [Member]
Jun. 30, 2013
Collateralized Mortgage Backed Securities [Member]
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
Collateralized Mortgage Backed Securities [Member]
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
Collateralized Mortgage Backed Securities [Member]
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
Collateralized Mortgage Backed Securities [Member]
Fair value [Member]
Jun. 30, 2013
Municipal Bonds
Fair Value, Inputs, Level 1 [Member]
Dec. 31, 2012
Municipal Bonds
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
Municipal Bonds
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2012
Municipal Bonds
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
Municipal Bonds
Fair Value, Inputs, Level 3 [Member]
Dec. 31, 2012
Municipal Bonds
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
Municipal Bonds
Fair value [Member]
Dec. 31, 2012
Municipal Bonds
Fair value [Member]
Jun. 30, 2013
Asset-backed Securities
Fair Value, Inputs, Level 1 [Member]
Dec. 31, 2012
Asset-backed Securities
Fair Value, Inputs, Level 1 [Member]
Jun. 30, 2013
Asset-backed Securities
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2012
Asset-backed Securities
Fair Value, Inputs, Level 2 [Member]
Jun. 30, 2013
Asset-backed Securities
Fair Value, Inputs, Level 3 [Member]
Dec. 31, 2012
Asset-backed Securities
Fair Value, Inputs, Level 3 [Member]
Jun. 30, 2013
Asset-backed Securities
Fair value [Member]
Dec. 31, 2012
Asset-backed Securities
Fair value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                                                                                                                                          
Fair Value, Equity Level Transfer 0                                                                                                                                        
Available-for-sale Securities, Fair Value Disclosure   $ 0 $ 0 $ 172,467 $ 183,787 $ 0 $ 0 $ 172,467 $ 183,787 $ 0 $ 0 $ 38,965 $ 37,357 $ 0 $ 0 $ 38,965 $ 37,357 $ 0 $ 0 $ 58,970 $ 55,748 $ 0 $ 0 $ 58,970 $ 55,748 $ 0 $ 0 $ 4,409 $ 4,414 $ 0 $ 0 $ 4,409 $ 4,414 $ 0 $ 0 $ 2,304 $ 22,267 $ 0 $ 0 $ 2,304 $ 22,267 $ 0 $ 0 $ 26,504 $ 25,867 $ 0 $ 0 $ 26,504 $ 25,867 $ 0 $ 1,147 $ 0 $ 1,147 $ 0 $ 0 $ 19,590 $ 11,568 $ 0 $ 0 $ 19,590 $ 11,568 $ 0 $ 0 $ 20,578 $ 26,566 $ 0 $ 0 $ 20,578 $ 26,566