Properties and Equipment Property and equipment, net (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 103,040	$ 97,249
Accumulated depreciation	(82,512)	(75,159)
Property and equipment, net	20,528	22,090
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	46,427	40,281
Equipment and Furniture [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	19,429	18,881
Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	28,249	29,538
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 8,935	$ 8,549