Fair Value Measurements - Assets And Liabilities Measured And Recorded At Fair Value On A Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands | Jun. 30, 2017 | Dec. 31, 2016 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | $ 285,038 | $ 387,671 |
Fair value liabilities measured on a recurring basis | (22,466) | (25,224) |
Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 58,684 | 141,658 |
Fair value liabilities measured on a recurring basis | 0 | 0 |
Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 215,770 | 235,645 |
Fair value liabilities measured on a recurring basis | (16,751) | (19,951) |
Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 10,584 | 10,368 |
Fair value liabilities measured on a recurring basis | (5,715) | (5,273) |
Cash and cash equivalents/Short-term marketable securities [Member] | Corporate Debt Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 72,596 | 76,568 |
Cash and cash equivalents/Short-term marketable securities [Member] | Corporate Debt Securities [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Cash and cash equivalents/Short-term marketable securities [Member] | Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 72,596 | 76,568 |
Cash and cash equivalents/Short-term marketable securities [Member] | Corporate Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Cash and cash equivalents/Short-term marketable securities [Member] | Foreign Government Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 2,243 | |
Cash and cash equivalents/Short-term marketable securities [Member] | Foreign Government Obligations [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | |
Cash and cash equivalents/Short-term marketable securities [Member] | Foreign Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 2,243 | |
Cash and cash equivalents/Short-term marketable securities [Member] | Foreign Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | |
Cash and cash equivalents/Short-term marketable securities [Member] | U.S. Treasuries / Agencies [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 48,737 | 40,516 |
Cash and cash equivalents/Short-term marketable securities [Member] | U.S. Treasuries / Agencies [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Cash and cash equivalents/Short-term marketable securities [Member] | U.S. Treasuries / Agencies [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 48,737 | 40,516 |
Cash and cash equivalents/Short-term marketable securities [Member] | U.S. Treasuries / Agencies [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Cash and cash equivalents/Short-term marketable securities [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 58,684 | 141,658 |
Cash and cash equivalents/Short-term marketable securities [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 58,684 | 141,658 |
Cash and cash equivalents/Short-term marketable securities [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Cash and cash equivalents/Short-term marketable securities [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Long-term marketable securities [Member] | Corporate Debt Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 28,423 | 29,353 |
Long-term marketable securities [Member] | Corporate Debt Securities [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Long-term marketable securities [Member] | Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 28,423 | 29,353 |
Long-term marketable securities [Member] | Corporate Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Long-term marketable securities [Member] | Foreign Government Obligations [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | | 2,238 |
Long-term marketable securities [Member] | Foreign Government Obligations [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | | 0 |
Long-term marketable securities [Member] | Foreign Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | | 2,238 |
Long-term marketable securities [Member] | Foreign Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | | 0 |
Long-term marketable securities [Member] | U.S. Treasuries / Agencies [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 63,771 | 86,970 |
Long-term marketable securities [Member] | U.S. Treasuries / Agencies [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Long-term marketable securities [Member] | U.S. Treasuries / Agencies [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 63,771 | 86,970 |
Long-term marketable securities [Member] | U.S. Treasuries / Agencies [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Long-term marketable securities [Member] | Auction Rate Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 10,584 | 10,368 |
Long-term marketable securities [Member] | Auction Rate Securities [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Long-term marketable securities [Member] | Auction Rate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 0 | 0 |
Long-term marketable securities [Member] | Auction Rate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value assets measured on recurring basis | 10,584 | 10,368 |
Accounts payable and accrued expenses [Member] | Cubiware Contingent Consideration [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | (2,604) | (1,988) |
Accounts payable and accrued expenses [Member] | Cubiware Contingent Consideration [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | 0 | 0 |
Accounts payable and accrued expenses [Member] | Cubiware Contingent Consideration [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | 0 | 0 |
Accounts payable and accrued expenses [Member] | Cubiware Contingent Consideration [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | (2,604) | (1,988) |
Accounts payable and accrued expenses [Member] | Interest Rate Swaps [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | | (648) |
Accounts payable and accrued expenses [Member] | Interest Rate Swaps [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | | 0 |
Accounts payable and accrued expenses [Member] | Interest Rate Swaps [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | | (648) |
Accounts payable and accrued expenses [Member] | Interest Rate Swaps [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | | 0 |
Other long-term liabilities [Member] | Cubiware Contingent Consideration [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | (3,111) | (3,285) |
Other long-term liabilities [Member] | Cubiware Contingent Consideration [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | 0 | 0 |
Other long-term liabilities [Member] | Cubiware Contingent Consideration [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | 0 | 0 |
Other long-term liabilities [Member] | Cubiware Contingent Consideration [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | (3,111) | (3,285) |
Other long-term liabilities [Member] | Interest Rate Swaps [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | (16,751) | (19,303) |
Other long-term liabilities [Member] | Interest Rate Swaps [Member] | Quoted Prices In Active Markets (Level 1) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | 0 | 0 |
Other long-term liabilities [Member] | Interest Rate Swaps [Member] | Significant Other Observable Inputs (Level 2) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | (16,751) | (19,303) |
Other long-term liabilities [Member] | Interest Rate Swaps [Member] | Significant Unobservable Inputs (Level 3) [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fair value liabilities measured on a recurring basis | $ 0 | $ 0 |