Fair Value Measures (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands | Mar. 31, 2017 | Dec. 31, 2016 | Mar. 31, 2016 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | $ 452,532 | $ 394,914 | $ 295,208 |
Total liabilities measured at fair value | | 354 | 286 | 5,173 |
Level 1 [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | 346,268 | 381,779 | 239,952 |
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 | | 106,264 | 13,135 | 55,256 |
Total liabilities measured at fair value | | 354 | 286 | 5,173 |
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 | | 354 | 286 | 4,251 |
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 | | 354 | 286 | 4,251 |
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 | | | | 922 |
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 | | | | 922 |
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 | | 246,245 | 299,769 | 147,379 |
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 | | 246,245 | 299,769 | 147,379 |
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 | | 90,927 | 73,127 | 84,580 |
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 | | 90,927 | 73,127 | 84,580 |
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 | | |
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] | Repurchase Agreements [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | | | 30,000 |
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 |
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 | | | | 30,000 |
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 |
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 | | 64,189 | | 3,999 |
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 | | 64,189 | | 3,999 |
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] | 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] | 33,817 | | 20,778 |
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 |
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] | 33,817 | | 20,778 |
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 |
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 | | 653 | 472 | 449 |
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 | | 653 | 472 | 449 |
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 | 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 | 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 | | 6,639 | 11,166 | 416 |
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 | | 6,639 | 11,166 | 416 |
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] | Mutual Fund Shares [Member] | | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | | |
Total assets measured at fair value | | 8,443 | 8,411 | 7,544 |
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 | | 8,443 | 8,411 | 7,544 |
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 | | 1,619 | 1,969 | 63 |
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 | 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 | | 1,619 | 1,969 | $ 63 |
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 | $ 0 | |
| |
[1] | Level 1 Level 2 Level 3 TotalAssets: Cash equivalents: Money market funds$147,379 $— $— $147,379Time deposits84,580 — — 84,580Reverse repurchase agreements— 30,000 — 30,000U.S. Government-backed municipal bonds— 3,999 — 3,999Available-for-sale short-term investments (1): U.S. Government-backed municipal bonds— 20,778 — 20,778Other short-term investments: Mutual funds shares449 — — 449Other current assets: Derivative financial instruments (Note 10)— 416 — 416Other non-current assets: Derivative financial instruments (Note 10)— 63 — 63Mutual fund shares7,544 — — 7,544Total assets measured at fair value$239,952 $55,256 $— $295,208Liabilities: Accrued liabilities: Derivative financial instruments (Note 10)$— $4,251 $— $4,251Other long-term liabilities Derivative financial instruments (Note 10)— 922 — 922Total liabilities measured at fair value$— $5,173 $— $5,173 | |