Basis of Presentation and Summary of Significant Accounting Policies - Accounting Pronouncements Adopted in the Current Year (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	$ 396,388	$ 392,072	$ 376,501
Net cash used in investing activities	121,846	13,019	(99,147)
Net cash used in financing activities	(588,180)	(393,700)	(283,949)
Income tax benefit	$ 13,027	30,836	18,842
As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		394,139	377,724
Net cash used in investing activities		14,704	(97,773)
Net cash used in financing activities		(393,301)	(269,496)
SEC Rule Change | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax benefit		32,126	25,208
Gain on dispositions of real estate and the Asset Management Business		299,559	393,790
SEC Rule Change | Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax benefit		(1,290)	(6,366)
Gain on dispositions of real estate and the Asset Management Business		1,290	6,366
ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities			(1,223)
Net cash used in investing activities			(1,374)
Net cash used in financing activities			$ (14,453)
ASU 2016-18 | Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		(2,067)
Net cash used in investing activities		(1,685)
Net cash used in financing activities		$ (399)