Equipment and Leasehold Improvements (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, plant and equipment
Total cost	$ 70,458	$ 60,865
Less accumulated depreciation and amortization	50,447	45,281
Equipment and leasehold improvements, net	20,011	15,584
Depreciation and amortization	5,166	5,464	$ 5,037
Software
Property, plant and equipment
Total cost	42,516	36,161
Computer equipment
Property, plant and equipment
Total cost	12,412	9,195
Leasehold improvements
Property, plant and equipment
Total cost	8,264	8,264
Other equipment
Property, plant and equipment
Total cost	3,132	3,116
Furniture and fixtures
Property, plant and equipment
Total cost	$ 4,134	$ 4,129

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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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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