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Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands |  | 12 Months Ended
--- | --- | ---
Dec. 14, 2018 | Dec. 31, 2018
Percentage holding required to account investments under non-marketable equity investments |  | 20.00%
Percentage of dividend | 20.00% |
Maximum [Member] |  |
Range of total assets and liabilities expected to be added to balance sheet from adoption of ASU No. 2016-02 - Leases |  | $ 11,000
Minimum [Member] |  |
Range of total assets and liabilities expected to be added to balance sheet from adoption of ASU No. 2016-02 - Leases |  | $ 9,000
Building [Member] | Maximum [Member] |  |
Estimated useful lives |  | 40 years
Leasehold Improvements [Member] | Minimum [Member] |  |
Estimated useful lives |  | 10 years
Software, Equipment, Furniture and Fixtures [Member] | Maximum [Member] |  |
Estimated useful lives |  | 7 years
Software, Equipment, Furniture and Fixtures [Member] | Minimum [Member] |  |
Estimated useful lives |  | 3 years

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