Consolidation - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets
Cash equivalents	$ 163,053	$ 287,126
Total assets measured at fair value	263,863	374,279
Liabilities
Total liabilities measured at fair value	54,910	78,100
Level 1
Assets
Cash equivalents	163,053	287,126
Total assets measured at fair value	263,863	374,279
Liabilities
Total liabilities measured at fair value	0	0
Level 2
Assets
Cash equivalents	0	0
Total assets measured at fair value	0	0
Liabilities
Total liabilities measured at fair value	0	0
Level 3
Assets
Cash equivalents	0	0
Total assets measured at fair value	0	0
Liabilities
Total liabilities measured at fair value	54,910	78,100
Fair Value, Measurements, Recurring | Consolidated Investment Products
Assets
Cash equivalents	153,549	249,003
Total assets measured at fair value	2,178,535	2,439,116
Liabilities
Notes payable	1,911,579	2,083,314
Short sales	511	414
Total liabilities measured at fair value	1,912,090	2,083,728
Fair Value, Measurements, Recurring | Debt investments | Consolidated Investment Products
Assets
Investments	1,994,549	2,161,571
Fair Value, Measurements, Recurring | Equity investments | Consolidated Investment Products
Assets
Investments	30,437	28,542
Fair Value, Measurements, Recurring | Level 1 | Consolidated Investment Products
Assets
Cash equivalents	153,549	249,003
Total assets measured at fair value	181,266	274,249
Liabilities
Notes payable	0	0
Short sales	511	414
Total liabilities measured at fair value	511	414
Fair Value, Measurements, Recurring | Level 1 | Debt investments | Consolidated Investment Products
Assets
Investments	278	243
Fair Value, Measurements, Recurring | Level 1 | Equity investments | Consolidated Investment Products
Assets
Investments	27,439	25,003
Fair Value, Measurements, Recurring | Level 2 | Consolidated Investment Products
Assets
Cash equivalents	0	0
Total assets measured at fair value	1,953,729	2,121,286
Liabilities
Notes payable	1,911,579	2,083,314
Short sales	0	0
Total liabilities measured at fair value	1,911,579	2,083,314
Fair Value, Measurements, Recurring | Level 2 | Debt investments | Consolidated Investment Products
Assets
Investments	1,952,096	2,119,082
Fair Value, Measurements, Recurring | Level 2 | Equity investments | Consolidated Investment Products
Assets
Investments	1,633	2,204
Fair Value, Measurements, Recurring | Level 3 | Consolidated Investment Products
Assets
Cash equivalents	0	0
Total assets measured at fair value	43,540	43,581
Liabilities
Notes payable	0	0
Short sales	0	0
Total liabilities measured at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Debt investments | Consolidated Investment Products
Assets
Investments	42,175	42,246
Fair Value, Measurements, Recurring | Level 3 | Equity investments | Consolidated Investment Products
Assets
Investments	$ 1,365	$ 1,335