Summary of Restructuring Charges (Detail) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 52	$ 4,170	$ 70	$ 5,647
Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges		5		867
Employee and office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	52	515	70	675
Other incremental costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		150		605
Lease assignment charge
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 3,500		$ 3,500