Revenues from Contracts with Customers - Schedule of Revenues from Contracts with Customers and Our Other Sources of Revenues (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue
Revenues from contracts with customers:	$ 1,435,401	$ 1,842,402	$ 1,700,786
Revenues	1,904,998	2,218,132	2,047,579
Gains from mortgage banking activities/originations, net
Disaggregation of Revenue
Other sources of revenue	310,914	198,085	182,264
Servicing fees and other
Disaggregation of Revenue
Other sources of revenue	158,683	177,645	164,529
Leasing and other commissions
Disaggregation of Revenue
Revenues from contracts with customers:	513,842	854,780	817,435
Revenues	513,842	854,780	817,435
Capital markets commissions
Disaggregation of Revenue
Revenues from contracts with customers:	454,106	541,255	468,904
Management services
Disaggregation of Revenue
Revenues from contracts with customers:	$ 467,453	$ 446,367	$ 414,447