Restructuring plan (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment, Continuing Operations [Member]
Restructuring Cost And Reserve [Line Items]
Personnel costs	$ 104,542	$ 108,352	$ 307,943	$ 322,292
Net occupancy expenses	21,203	21,386	62,830	62,937
Equipment Expense	12,370	11,387	35,826	34,492
Professional fees	67,649	69,237	201,672	203,989
Other operating expenses	30,418	21,998	73,276	65,682
Restructuring Charges Member
Restructuring Cost And Reserve [Line Items]
Personnel costs	6,194		9,824
Net occupancy expenses	152		423
Equipment Expense	141		331
Professional fees	1,431		1,879
Other operating expenses	372		407
Restructuring Charges Member | Segment, Continuing Operations [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring Charges	$ 8,290	$ 0	$ 12,864	$ 0