v2.4.0.8

Financial Instruments and Fair Value , Investments (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2013 | Dec. 31, 2012
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | $ 726,001 | $ 614,853
Unrealized Gains | 1,565 | 1,925
Unrealized Losses | (394) | (167)
Total | 727,172 | 616,611
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |
Less Than 12 Months, Fair Value | 205,428 | 141,470
Less Than 12 Months, Unrealized Losses | (394) | (162)
12 Months or Greater, Fair Value | 500 | 5,010
12 Months or Greater, Unrealized Losses | 0 | (5)
Total, Fair Value | 205,928 | 146,480
Total, Unrealized Losses | (394) | (167)
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] |  |
Due within one year | 375,497 | 290,719
Due within one to three years | 351,675 | 325,892
Total | 727,172 | 616,611
U.S. government and agency securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 2,000 |
Unrealized Gains | 1 |
Unrealized Losses | 0 |
Total | 2,001 |
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] |  |
Total | 2,001 |
Corporate debt securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 603,185 | 529,738
Unrealized Gains | 1,506 | 1,814
Unrealized Losses | (374) | (161)
Total | 604,317 | 531,391
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |
Less Than 12 Months, Fair Value | 182,795 | 133,006
Less Than 12 Months, Unrealized Losses | (374) | (156)
12 Months or Greater, Fair Value | 500 | 5,010
12 Months or Greater, Unrealized Losses | 0 | (5)
Total, Fair Value | 183,295 | 138,016
Total, Unrealized Losses | (374) | (161)
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] |  |
Total | 604,317 | 531,391
Commercial paper [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 69,356 | 39,229
Unrealized Gains | 7 | 22
Unrealized Losses | 0 | (6)
Total | 69,363 | 39,245
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |
Less Than 12 Months, Fair Value | 7,897 | 8,464
Less Than 12 Months, Unrealized Losses | 0 | (6)
12 Months or Greater, Fair Value | 0 | 0
12 Months or Greater, Unrealized Losses | 0 | 0
Total, Fair Value | 7,897 | 8,464
Total, Unrealized Losses | 0 | (6)
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] |  |
Total | 69,363 | 39,245
Municipal bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 38,815 | 36,787
Unrealized Gains | 48 | 83
Unrealized Losses | (20) | 0
Total | 38,843 | 36,870
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |
Less Than 12 Months, Fair Value | 14,736 |
Less Than 12 Months, Unrealized Losses | (20) |
12 Months or Greater, Fair Value | 0 |
12 Months or Greater, Unrealized Losses | 0 |
Total, Fair Value | 14,736 |
Total, Unrealized Losses | (20) |
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] |  |
Total | 38,843 | 36,870
Certificates of deposit and term deposits [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized Cost | 12,645 | 9,099
Unrealized Gains | 3 | 6
Unrealized Losses | 0 | 0
Total | 12,648 | 9,105
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] |  |
Total | $ 12,648 | $ 9,105

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