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Summary of Significant Accounting Policies (Details) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 USD ($) plan | Dec. 31, 2017 USD ($) | Jan. 01, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Number of compensation plans | plan | 3 |  |
Award vesting period (in years) | 4 years |  |
ESPP, market price discount percentage | 5.00% |  |
Available-for-Sale | $ 317,535 | $ 300,200 |
Accounting Standards Update 2018-02 |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Adjustments to additional paid in capital, income tax rate reduction |  | 1,600 |
Accounting Standards Update 2014-09 |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Impact of ASU adoption |  | (102) |
Fair Value, Measurements, Recurring |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Available-for-Sale | $ 317,535 | 300,200 |
Equity Securities |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Available-for-Sale |  | 1,561 |
Equity Securities | Fair Value, Measurements, Recurring |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Available-for-Sale |  | $ 1,561 |
Minimum |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Intangible asset, useful life (in years) | 10 years |  |
Maximum |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Intangible asset, useful life (in years) | 15 years |  |
Building and Building Improvements | Minimum |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Property, plant and equipment, useful life | 20 years |  |
Building and Building Improvements | Maximum |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Property, plant and equipment, useful life | 40 years |  |
Furniture and Fixtures | Minimum |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Property, plant and equipment, useful life | 7 years |  |
Furniture and Fixtures | Maximum |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Property, plant and equipment, useful life | 10 years |  |
Computer Equipment | Minimum |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Property, plant and equipment, useful life | 5 years |  |
Computer Equipment | Maximum |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Property, plant and equipment, useful life | 7 years |  |
Equity Option |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Award vesting period (in years) | 4 years |  |
Restricted Stock Units (RSUs) |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Award vesting period (in years) | 3 years |  |
Scenario, Forecast | Subsequent Event | Accounting Standards Update 2016-02 |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Operating lease, right of use asset |  |  | $ 8,000
Operating lease, liability |  |  | $ 8,000

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