Restructuring and Other Special Charges and Related Liability Balances (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Expense	$ 6,828	$ 13,167		$ 19,995	$ 40,358
Restructuring November 2012 Plan
Restructuring Cost and Reserve [Line Items]
Accrual, Beginning Balance		11,985	5,248	11,985
Expense				19,995
Cash Payments			(2,307)	(21,417)
Non-Cash Utilization				(5,315)
Accrual, Ending Balance			2,941	5,248
Restructuring November 2012 Plan | Workforce reduction
Restructuring Cost and Reserve [Line Items]
Accrual, Beginning Balance		11,902	1,057	11,902
Expense				9,645
Cash Payments			(648)	(18,669)
Non-Cash Utilization				(1,821)
Accrual, Ending Balance			409	1,057
Restructuring November 2012 Plan | Consolidation of office facilities
Restructuring Cost and Reserve [Line Items]
Accrual, Beginning Balance			4,063
Expense				6,028
Cash Payments			(1,535)	(1,965)
Accrual, Ending Balance			2,528	4,063
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, Beginning Balance		83	128	83
Expense				828
Cash Payments			(124)	(783)
Accrual, Ending Balance			$ 4	$ 128