Unconsolidated Entities - Summary of Strategic Capital Revenues Recognized in Consolidated Statements of Income Related to Co-Investment Ventures (Detail) - Unconsolidated Co-Investment Ventures [Member] - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Recurring fees		$ 62,117	$ 54,644
Transactional fees		11,348	15,624
Promote revenues		0	62,544
Total strategic capital revenues from unconsolidated co-investment ventures	[1]	$ 73,465	$ 132,812

[1] These amounts exclude strategic capital revenues from other ventures