Research And Development	12 Months Ended
Dec. 31, 2017
Research and Development [Abstract]
Research And Development	Research and Development Research and development costs are expensed when incurred. These costs were $58.5 million, $61.5 million and $62.8 million in 2017, 2016 and 2015, respectively.

- Definition

The entire disclosure for research, development, and computer software activities, including contracts and arrangements to be performed for others and with federal government. Includes costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility and in-process research and development acquired in a business combination consummated during the period.

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