Restructuring and Other Special Charges and Related Liability Balances (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Restructuring January 2012 Plan
Restructuring Cost and Reserve [Line Items]
Accrual at December 31, 2012	$ 5,178
Cash Payments	(1,385)
Accrual at June 30, 2013	3,793
Restructuring January 2012 Plan | Workforce reduction
Restructuring Cost and Reserve [Line Items]
Accrual at December 31, 2012	1,191
Cash Payments	(386)
Accrual at June 30, 2013	805
Restructuring January 2012 Plan | Consolidation of office facilities
Restructuring Cost and Reserve [Line Items]
Accrual at December 31, 2012	3,938
Cash Payments	(973)
Accrual at June 30, 2013	2,965
Restructuring January 2012 Plan | Other costs and professional fees
Restructuring Cost and Reserve [Line Items]
Accrual at December 31, 2012	49
Cash Payments	(26)
Accrual at June 30, 2013	23
Restructuring November 2012 Plan
Restructuring Cost and Reserve [Line Items]
Accrual at December 31, 2012	11,985
Expense	19,995
Cash Payments	(16,087)
Non-Cash Utilization	(5,315)
Accrual at June 30, 2013	10,578
Restructuring November 2012 Plan | Workforce reduction
Restructuring Cost and Reserve [Line Items]
Accrual at December 31, 2012	11,902
Expense	9,645
Cash Payments	(14,338)
Non-Cash Utilization	(1,821)
Accrual at June 30, 2013	5,388
Restructuring November 2012 Plan | Consolidation of office facilities
Restructuring Cost and Reserve [Line Items]
Expense	6,028
Cash Payments	(1,193)
Accrual at June 30, 2013	4,835
Restructuring November 2012 Plan | Impairment of Assets
Restructuring Cost and Reserve [Line Items]
Expense	3,494
Non-Cash Utilization	(3,494)
Restructuring November 2012 Plan | Other costs and professional fees
Restructuring Cost and Reserve [Line Items]
Accrual at December 31, 2012	83
Expense	828
Cash Payments	(556)
Accrual at June 30, 2013	$ 355