Consolidation - Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Cash and cash equivalents		$ 201,705
Noncontrolling interests	$ (63,845)	(57,481)	$ (4,178)	$ (37,266)
VOEs
Variable Interest Entity [Line Items]
Cash and cash equivalents	2,665	1,029
Investments	22,223	12,923
Other assets	1,563	228
Notes payable	0	0
Securities purchased payable and other liabilities	(2,964)	(823)
Noncontrolling interests	(3,865)	(2,348)
Net interests in CIP	19,622	11,009
CLOs
Variable Interest Entity [Line Items]
Cash and cash equivalents	97,130	51,363
Investments	1,976,148	1,709,266
Other assets	21,450	30,426
Notes payable	(1,834,535)	(1,620,260)
Securities purchased payable and other liabilities	(164,887)	(69,737)
Noncontrolling interests	(10,558)	(13,958)
Net interests in CIP	84,748	87,100
Other
Variable Interest Entity [Line Items]
Cash and cash equivalents	363	559
Investments	31,739	27,379
Other assets	599	403
Notes payable	0	0
Securities purchased payable and other liabilities	(200)	(146)
Noncontrolling interests	(1,564)	(36)
Net interests in CIP	$ 30,937	$ 28,159