Unconsolidated Entities - Earnings on Investment in Co-Investment Ventures (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	$ 97,220	$ 31,676	$ 59,935
Private capital revenue	179,472	126,779	137,619
Unconsolidated co-investment ventures [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	94,654	25,703	49,326
Total Investment management revenue	177,185	125,185	127,200
Private capital revenue	181,192	125,720	133,143
Unconsolidated co-investment ventures [Member] | Development management and other income - Europe [Member]
Schedule of Equity Method Investments [Line Items]
Total Investment management revenue	4,007	535	5,943
Unconsolidated co-investment ventures [Member] | Americas [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	21,724	(7,843)	22,709
Total Investment management revenue	70,642	68,142	67,293
Unconsolidated co-investment ventures [Member] | Europe [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	63,839	31,174	25,709
Total Investment management revenue	63,794	37,173	45,758
Unconsolidated co-investment ventures [Member] | Asia [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	9,091	2,372	908
Total Investment management revenue	$ 42,749	$ 19,870	$ 14,149