Other Balance Sheet Items (Property And Equipment, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Land	$ 31,141	$ 31,141
Buildings and building improvements	246,654	246,237
Computer equipment and software	462,469	441,732
Capital work in progress	4,024	4,246
Office equipment and furniture	6,472	6,203
Leasehold improvements	1,403	1,350
Total cost	752,163	730,909
Less: accumulated depreciation and amortization	(488,650)	(464,784)
Total property and equipment, net	$ 263,513	$ 266,125

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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The carrying amount of capitalized computer software costs net of accumulated amortization as of the balance sheet date.

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount before accumulated depreciation of equipment commonly used in offices and stores that have no permanent connection to the structure of a building or utilities. Examples include, but are not limited to, desks, chairs, tables, and bookcases.

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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

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Amount before accumulated depreciation of additions or improvements to assets held under a lease arrangement.

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