Segments - Schedule of Capital Expenditures by Segment (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Capital expenditures	$ 171,242	$ 156,358	$ 150,232
Global Investment Management [Member]
Segment Reporting Information [Line Items]
Capital expenditures	6,596	9,364	29,811
Development Services [Member]
Segment Reporting Information [Line Items]
Capital expenditures	1,358	138	197
Americas [Member]
Segment Reporting Information [Line Items]
Capital expenditures	109,297	112,570	96,785
EMEA [Member]
Segment Reporting Information [Line Items]
Capital expenditures	30,851	18,691	11,719
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Capital expenditures	$ 23,140	$ 15,595	$ 11,720