Fair Value Measures (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands | Jun. 30, 2015 | Dec. 31, 2014 | Jun. 30, 2014 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | $ 308,412 | $ 232,634 | $ 262,355 |
Total liabilities measured at fair value | | 766 | 924 | 1,743 |
Level 1 [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | 226,602 | 145,823 | 179,400 |
Total liabilities measured at fair value | | 0 | 0 | 0 |
Level 2 [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | 81,810 | 86,811 | 82,955 |
Total liabilities measured at fair value | | 766 | 924 | 1,743 |
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 | 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 | | 766 | 924 | 1,731 |
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 | 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 | | 766 | 924 | 1,731 |
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 | 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 | | | | 12 |
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 | | | | 12 |
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 | | 116,316 | 94,112 | 147,953 |
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 | | 116,316 | 94,112 | 147,953 |
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 | | 102,756 | 45,187 | 39,972 |
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 | | 102,756 | 45,187 | 25,148 |
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 | | 14,824 |
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 | | | 1,470 | |
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 | | | 1,470 | |
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 | | 20,000 | 40,000 | 40,000 |
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 | 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 | | 20,000 | 40,000 | 40,000 |
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 | 0 |
Cash Equivalents [Member] | US Government Backed Municipal Bonds [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | 6,775 | 5,812 | |
Cash Equivalents [Member] | US 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] | US 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 | | 6,775 | 5,812 | |
Cash Equivalents [Member] | US 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] | Certificates of Deposit [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | [1] | 10,291 | 3,184 | 3,429 |
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 | [1] | 0 | 0 | 0 |
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 | [1] | 10,291 | 3,184 | 3,429 |
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 | [1] | 0 | 0 | 0 |
Available-For-Sale Short-Term Investments [Member] | US Government Backed Municipal Bonds [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | [1] | 35,481 | 23,598 | 4,584 |
Available-For-Sale Short-Term Investments [Member] | US 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 | [1] | 0 | 0 | 0 |
Available-For-Sale Short-Term Investments [Member] | US 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 | [1] | 35,481 | 23,598 | 4,584 |
Available-For-Sale Short-Term Investments [Member] | US 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 | [1] | 0 | 0 | 0 |
Short-term Investments [Member] | Mutual Fund Shares [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | 656 | 485 | 550 |
Short-term Investments [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 | | 656 | 485 | $ 550 |
Short-term Investments [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 | |
Short-term Investments [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 | |
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 | | 8,943 | 12,747 | $ 1,288 |
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 | |
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 | | 8,943 | 12,747 | $ 1,288 |
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 | |
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 | | 6,874 | 6,039 | 5,749 |
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 | | 6,874 | 6,039 | 5,749 |
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 |
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 | | | | 155 |
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 | | | | $ 155 |
| |
[1] | (1) Investments have remaining maturities of less than one year. | |