Summary of Significant Accounting Policies Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue from External Customer [Line Items]
Revenues	$ 483,930	$ 447,656
Leasing and other commissions
Revenue from External Customer [Line Items]
Revenues	140,439	172,471
Management services, servicing fees and other
Revenue from External Customer [Line Items]
Revenues	165,146	141,042
Capital Markets Commissions
Revenue from External Customer [Line Items]
Revenues	127,923	102,797
Gains from mortgage banking activities/originations, net
Revenue from External Customer [Line Items]
Revenues	$ 50,422	$ 31,346