Components of Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Computer hardware	$ 130,469	$ 122,619
Computer software	264,552	249,843
Furniture and equipment	113,912	108,917
Leasehold improvements	119,206	113,972
Other	13,228	15,143
Property and equipment, cost	641,367	610,494
Accumulated depreciation	(536,183)	(502,522)
Property and equipment, net	$ 105,184	$ 107,972