Property And Equipment, Net (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Property And Equipment, Net
Building	$ 39,601,000		$ 39,601,000		$ 39,003,000
Furniture and fixtures	16,725,000		16,725,000		15,846,000
Machinery and equipment	8,608,000		8,608,000		7,181,000
Computer equipment	57,844,000		57,844,000		54,940,000
Computer software	47,405,000		47,405,000		43,822,000
Leasehold improvements	17,688,000		17,688,000		15,438,000
Land	16,317,000		16,317,000		11,154,000
Property and equipment, gross	204,188,000		204,188,000		187,384,000
Less accumulated depreciation and amortization	(123,003,000)		(123,003,000)		(116,530,000)
Property and equipment, net	81,185,000		81,185,000		70,854,000
Depreciation and amortization expense	$ 3,800,000	$ 3,500,000	$ 7,600,000	$ 7,000,000