Goodwill and Other Intangible Assets - Schedule of Changes in Goodwill By Segment (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Americas [Member]	Dec. 31, 2012 Americas [Member]	Dec. 31, 2013 EMEA [Member]	Dec. 31, 2012 EMEA [Member]	Dec. 31, 2013 Asia Pacific [Member]	Dec. 31, 2012 Asia Pacific [Member]	Dec. 31, 2013 Global Investment Management [Member]	Dec. 31, 2012 Global Investment Management [Member]	Dec. 31, 2013 Development Services [Member]	Dec. 31, 2012 Development Services [Member]	Dec. 31, 2011 Development Services [Member]
Goodwill [Line Items]
Goodwill Gross, Beginning	$ 2,958,108	$ 2,896,913	$ 1,658,313	$ 1,641,748	$ 533,696	$ 494,116	$ 160,736	$ 160,197	$ 518,700	$ 514,189	$ 86,663	$ 86,663	$ 86,663
Accumulated impairment losses	(1,068,506)	(1,068,506)	(798,290)	(798,290)	(138,631)	(138,631)			(44,922)	(44,922)	(86,663)	(86,663)	(86,663)
Goodwill, Net of impairment losses	1,889,602	1,828,407	860,023	843,458	395,065	355,485	160,736	160,197	473,778	469,267
Purchase accounting entries related to acquisitions	399,418	46,318	60,552	15,980	342,035	31,440	(3,169)	1,175		(2,277)
Foreign exchange movement	1,454	14,877	(1,228)	585	14,407	8,140	(19,074)	(636)	7,349	6,788
Goodwill Gross, Ending	3,358,980	2,958,108	1,717,637	1,658,313	890,138	533,696	138,493	160,736	526,049	518,700	86,663	86,663	86,663
Accumulated impairment losses	(1,068,506)	(1,068,506)	(798,290)	(798,290)	(138,631)	(138,631)			(44,922)	(44,922)	(86,663)	(86,663)	(86,663)
Goodwill, Net of impairment losses	$ 2,290,474	$ 1,889,602	$ 919,347	$ 860,023	$ 751,507	$ 395,065	$ 138,493	$ 160,736	$ 481,127	$ 473,778