Property And Equipment, Net (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Property And Equipment, Net
Building	$ 39,276,000		$ 39,276,000		$ 39,003,000
Furniture and fixtures	16,915,000		16,915,000		15,846,000
Machinery and equipment	8,857,000		8,857,000		7,181,000
Computer equipment	59,784,000		59,784,000		54,940,000
Computer software	49,296,000		49,296,000		43,822,000
Leasehold improvements	20,374,000		20,374,000		15,438,000
Land	16,317,000		16,317,000		11,154,000
Property and equipment, gross	210,819,000		210,819,000		187,384,000
Less accumulated depreciation and amortization	(126,343,000)		(126,343,000)		(116,530,000)
Property and equipment, net	84,476,000		84,476,000		70,854,000
Depreciation and amortization expense	$ 3,500,000	$ 3,400,000	$ 11,100,000	$ 10,400,000