Property and equipment (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property and Equipment [Abstract]
Buildings and improvements	$ 37,356	$ 37,356
Computer and other equipment	21,763	23,771
Software	4,159	4,942
Furniture and fixtures	2,728	2,698
Leasehold improvements	3,823	3,826
Property, Plant and Equipment, Gross	69,829	72,593
Less: Accumulated depreciation and amortization	(48,052)	(45,392)
Property and equipment, net	$ 21,777	$ 27,201

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount of long-lived 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, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived 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, furniture and fixtures, and computer equipment.

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