Unconsolidated Entities - Earnings on Investment in Co-Investment Ventures (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	$ 134,288	$ 97,220	$ 31,676
Strategic capital revenue	219,871us-gaap_ManagementFeesRevenue	179,472us-gaap_ManagementFeesRevenue	126,779us-gaap_ManagementFeesRevenue
Unconsolidated Co-Investment Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	131,048	94,654	25,703
Total strategic capital revenue	218,350	177,185	125,185
Strategic capital revenue	223,774	181,192	125,720
Unconsolidated Co-Investment Ventures [Member] \| Development Management and Other Income [Member]
Schedule of Equity Method Investments [Line Items]
Total strategic capital revenue	5,424	4,007	535
Unconsolidated Co-Investment Ventures [Member] \| Americas [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	8,596	21,724	(7,843)
Total strategic capital revenue	94,354	70,642	68,142
Unconsolidated Co-Investment Ventures [Member] \| Europe [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	108,430	63,839	31,174
Total strategic capital revenue	86,487	63,794	37,173
Unconsolidated Co-Investment Ventures [Member] \| Asia [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated entities, net	14,022	9,091	2,372
Total strategic capital revenue	$ 37,509	$ 42,749	$ 19,870

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

+ References+ Details