Fair Value Measures (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) | 9 Months Ended | | |
In Thousands, unless otherwise specified | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2013 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | $118,911 | $367,420 | | $242,230 | |
Total liabilities measured at fair value | ' | 1,247 | | 599 | |
Investments, remaining maturity, minimum | '3 months | ' | | ' | |
Investments, remaining maturity, maximum | '2 years | ' | | ' | |
Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 110,217 | 220,930 | | 183,293 | |
Total liabilities measured at fair value | ' | 0 | | 0 | |
Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 8,694 | 146,490 | | 58,937 | |
Total liabilities measured at fair value | ' | 1,247 | | 599 | |
Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Total liabilities measured at fair value | ' | 0 | | 0 | |
Accrued Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total liabilities measured at fair value | ' | 1,152 | | 599 | |
Accrued Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total liabilities measured at fair value | ' | 0 | | 0 | |
Accrued Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total liabilities measured at fair value | ' | 1,152 | | 599 | |
Accrued Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total liabilities measured at fair value | ' | 0 | | 0 | |
Other Long Term Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total liabilities measured at fair value | ' | 95 | | ' | |
Other Long Term Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total liabilities measured at fair value | ' | 0 | | ' | |
Other Long Term Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total liabilities measured at fair value | ' | 95 | | ' | |
Other Long Term Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total liabilities measured at fair value | ' | 0 | | ' | |
Cash Equivalents [Member] | Money Market Funds [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 79,266 | 175,624 | | 153,382 | |
Cash Equivalents [Member] | Money Market Funds [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 79,266 | 175,624 | | 153,382 | |
Cash Equivalents [Member] | Money Market Funds [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Cash Equivalents [Member] | Money Market Funds [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Cash Equivalents [Member] | Time Deposits [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 25,167 | 34,637 | | 25,092 | |
Cash Equivalents [Member] | Time Deposits [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 25,167 | 25,111 | | 25,092 | |
Cash Equivalents [Member] | Time Deposits [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 9,526 | | ' | |
Cash Equivalents [Member] | Time Deposits [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Cash Equivalents [Member] | Certificates of Deposit [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 735 | | ' | |
Cash Equivalents [Member] | Certificates of Deposit [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | | ' | |
Cash Equivalents [Member] | Certificates of Deposit [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 735 | | ' | |
Cash Equivalents [Member] | Certificates of Deposit [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | | ' | |
Cash Equivalents [Member] | Repurchase Agreements [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 45,000 | | 25,000 | |
Cash Equivalents [Member] | Repurchase Agreements [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | | 0 | |
Cash Equivalents [Member] | Repurchase Agreements [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 45,000 | | 25,000 | |
Cash Equivalents [Member] | Repurchase Agreements [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | | 0 | |
Cash Equivalents [Member] | U.S. Government-Backed Municipal Bonds [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 9,898 | | 3,218 | |
Cash Equivalents [Member] | U.S. Government-Backed Municipal Bonds [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | | 0 | |
Cash Equivalents [Member] | U.S. Government-Backed Municipal Bonds [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 9,898 | | 3,218 | |
Cash Equivalents [Member] | U.S. Government-Backed Municipal Bonds [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | | 0 | |
Available-For-Sale Short-Term Investments [Member] | Short-term municipal bond funds [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 15,004 | [1] | ' | |
Available-For-Sale Short-Term Investments [Member] | Short-term municipal bond funds [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 15,004 | [1] | ' | |
Available-For-Sale Short-Term Investments [Member] | Short-term municipal bond funds [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | [1] | ' | |
Available-For-Sale Short-Term Investments [Member] | Short-term municipal bond funds [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | [1] | ' | |
Available-For-Sale Short-Term Investments [Member] | Certificates of Deposit [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 9,546 | [1] | 1,470 | [1] |
Available-For-Sale Short-Term Investments [Member] | Certificates of Deposit [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | [1] | 0 | [1] |
Available-For-Sale Short-Term Investments [Member] | Certificates of Deposit [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 9,546 | [1] | 1,470 | [1] |
Available-For-Sale Short-Term Investments [Member] | Certificates of Deposit [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | [1] | 0 | [1] |
Available-For-Sale Short-Term Investments [Member] | Variable Rate Demand Obligation [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 52,105 | [1] | 27,320 | [1] |
Available-For-Sale Short-Term Investments [Member] | Variable Rate Demand Obligation [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | [1] | 0 | [1] |
Available-For-Sale Short-Term Investments [Member] | Variable Rate Demand Obligation [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 52,105 | [1] | 27,320 | [1] |
Available-For-Sale Short-Term Investments [Member] | Variable Rate Demand Obligation [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | [1] | 0 | [1] |
Available-For-Sale Short-Term Investments [Member] | U.S. Government-Backed Municipal Bonds [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 14,764 | [1] | ' | |
Available-For-Sale Short-Term Investments [Member] | U.S. Government-Backed Municipal Bonds [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | [1] | ' | |
Available-For-Sale Short-Term Investments [Member] | U.S. Government-Backed Municipal Bonds [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 14,764 | [1] | ' | |
Available-For-Sale Short-Term Investments [Member] | U.S. Government-Backed Municipal Bonds [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | [1] | ' | |
Trading Securities [Member] | Mutual Fund Shares [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 537 | 336 | | 259 | |
Trading Securities [Member] | Mutual Fund Shares [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 537 | 336 | | 259 | |
Trading Securities [Member] | Mutual Fund Shares [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Trading Securities [Member] | Mutual Fund Shares [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Other Current Assets [Member] | Derivative Financial Instruments, Assets [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 8,694 | 4,892 | | 1,929 | |
Other Current Assets [Member] | Derivative Financial Instruments, Assets [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Other Current Assets [Member] | Derivative Financial Instruments, Assets [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 8,694 | 4,892 | | 1,929 | |
Other Current Assets [Member] | Derivative Financial Instruments, Assets [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Non Current Assets [Member] | Derivative Financial Instruments, Assets [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 24 | | ' | |
Non Current Assets [Member] | Derivative Financial Instruments, Assets [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | | ' | |
Non Current Assets [Member] | Derivative Financial Instruments, Assets [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 24 | | ' | |
Non Current Assets [Member] | Derivative Financial Instruments, Assets [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | ' | 0 | | ' | |
Non Current Assets [Member] | Mutual Fund Shares [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 5,247 | 4,855 | | 4,560 | |
Non Current Assets [Member] | Mutual Fund Shares [Member] | Level 1 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 5,247 | 4,855 | | 4,560 | |
Non Current Assets [Member] | Mutual Fund Shares [Member] | Level 2 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | 0 | 0 | | 0 | |
Non Current Assets [Member] | Mutual Fund Shares [Member] | Level 3 [Member] | ' | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | | ' | |
Total assets measured at fair value | $0 | $0 | | $0 | |
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[1] | (1)B Investments have remaining maturities greater than three months but less than two years and are available for use in current opera |