SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ / shares in Units, € in Thousands			1 Months Ended			3 Months Ended								6 Months Ended			9 Months Ended		12 Months Ended
	Sep. 23, 2022 USD ($)	Jan. 15, 2021 $ / shares shares	Jul. 29, 2022 USD ($)	Dec. 31, 2021 USD ($) $ / shares shares	Jun. 30, 2018	Dec. 31, 2022 USD ($) shares	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) $ / shares shares	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2022 USD ($) shares	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2022 USD ($) segment shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)	May 31, 2022	May 30, 2022	Dec. 31, 2021 EUR (€) shares	Feb. 25, 2021	Nov. 30, 2020	Oct. 28, 2019 $ / shares shares
Summary of Significant Accounting Policies (Details) [Line Items]
Advertising costs																			$ 11,434,000	$ 3,681,000	$ 3,013,000
Recognized compensation expense																			$ 369,000	$ 758,000	377,000
Number of shares reserved for future issuance (in shares) | shares				450,717		362,986				450,717				362,986					362,986	450,717				450,717
Restricted cash				$ 927,000		$ 2,308,000				$ 927,000				$ 2,308,000					$ 2,308,000	$ 927,000
Depreciation and amortization																			5,677,000	3,865,000	3,632,000
Total assets measured at fair value				873,186,000		701,652,000				873,186,000				701,652,000					701,652,000	873,186,000
Net of unamortized costs, origination fees, premiums and discounts				9,304,000		3,851,000				9,304,000				3,851,000					3,851,000	9,304,000
Loans receivable, net unrealized losses				10,035,000		(54,439,000)				10,035,000				(54,439,000)					(54,439,000)	10,035,000	(22,033,000)
Financing receivable, nonaccrual						$ 7,153,000								$ 7,153,000					$ 7,153,000
Nonaccrual to outstanding, percent						1.00%								1.00%					1.00%
Loans receivable, at fair value				873,186,000		$ 701,652,000				873,186,000				$ 701,652,000					$ 701,652,000	873,186,000
Reporting units | segment																			6
Impairment charges																			$ 0	0	0
Intangible assets																			0	0	12,500,000
Impairment of intangible assets																			$ 4,174,000	0	0
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration]																			Restructuring charge
Partnership investment interests																			$ 70,063,000	77,383,000
Investment securities				59,745,000		94,109,000				59,745,000				94,109,000					94,109,000	59,745,000
Senior notes payable				1,606,560,000		1,721,751,000				1,606,560,000				1,721,751,000					1,721,751,000	1,606,560,000
Fair value				1,661,189,000		$ 1,431,787,000				1,661,189,000				$ 1,431,787,000					1,431,787,000	1,661,189,000
Forward exchange contracts (in Euro) | €																								€ 6,000
Transaction gains (losses)																			$ 2,224,000	1,256,000	(639,000)
Derivative Liability, Statement of Financial Position [Extensible Enumeration]						Accrued expenses and other liabilities								Accrued expenses and other liabilities					Accrued expenses and other liabilities
Equity investments				39,190,000		$ 41,298,000				39,190,000				$ 41,298,000					$ 41,298,000	39,190,000
Fair value				407,834,000		371,948,000				407,834,000				371,948,000					371,948,000	407,834,000
Total assets				5,851,919,000		6,111,202,000				5,851,919,000				6,111,202,000					6,111,202,000	5,851,919,000
Total liabilities				4,801,718,000		5,426,687,000				4,801,718,000				5,426,687,000					5,426,687,000	4,801,718,000
Total revenues						382,092,000	$ 312,117,000	$ 139,621,000	$ 246,840,000	400,314,000	$ 392,281,000	$ 318,966,000	$ 443,137,000		$ 386,461,000	$ 762,103,000	$ 698,578,000	$ 1,154,384,000	1,080,670,000	1,554,698,000	834,217,000
Income (loss) from equity method investments						285,000	$ (91,000)	$ (3,399,000)	$ 6,775,000	1,629,000	$ 1,149,000	$ (852,000)	$ 875,000		$ 3,376,000	$ 23,000	$ 3,285,000	$ 1,172,000	3,570,000	2,801,000	(623,000)
Equity interests issued and issuable																			850,000
Equity securities				2,800,000		35,648,000				2,800,000				35,648,000					35,648,000	2,800,000	11,133,000
Notes reduction																				133,453,000
Loans receivable exchanged for debt securities																				35,000,000
Operating lease right-of-use assets				56,969,000		88,593,000				56,969,000				88,593,000					88,593,000	56,969,000
Sale of equity securities																					26,238,000
Operating lease liabilities				$ 69,072,000		99,124,000				$ 69,072,000				99,124,000					99,124,000	69,072,000
Financing receivable																					61,687,000
Fund amount																					24,434,000
Notes payable																					37,253,000
Agent fees																			12,576,000	$ 66,263,000
Consummated units (in shares) | shares		1,413,045
sold price per unit (in dollars per share) | $ / shares		$ 46		$ 10.00						$ 10.00										$ 10.00
Assets held in trust				$ 345,000,000						$ 345,000,000										$ 345,000,000
Consummate business combination transaction term																				24 months
Consummate business combination transaction term, circumstance based																				27 months
Wealth Management Segment
Summary of Significant Accounting Policies (Details) [Line Items]
Impairment charges																			0
Total revenues																			234,257,000	$ 381,984,000	73,149,000
Bebe Stores Inc. ("bebe")
Summary of Significant Accounting Policies (Details) [Line Items]
Equity investments				36,662,000		40,383,000				36,662,000				40,383,000					40,383,000	36,662,000
Additional purchase of value				612,000
Fair value				43,472,000		25,423,000				43,472,000				25,423,000					25,423,000	43,472,000
Income (loss) from equity method investments																			17,423,000	8,366,000	6,383,000
Bebe Stores Inc. ("bebe")
Summary of Significant Accounting Policies (Details) [Line Items]
Total assets				78,761,000		94,401,000				78,761,000				94,401,000					94,401,000	78,761,000
Total liabilities				$ 40,173,000		45,858,000				$ 40,173,000				45,858,000					45,858,000	40,173,000
Total revenues																			55,452,000	50,745,000	$ 6,258,000
FaZeClan Holdings, Inc
Summary of Significant Accounting Policies (Details) [Line Items]
Noncontrolling interest, decrease from deconsolidation			$ 172,500,000																172,500,000
Deconsolidation, decrease in prepaid expenses and other assets			$ 172,584,000
FaZeClan Holdings, Inc | Incentive Fee
Summary of Significant Accounting Policies (Details) [Line Items]
Revenue from related parties														41,885,000
BRPM 250
Summary of Significant Accounting Policies (Details) [Line Items]
Noncontrolling interest, decrease from deconsolidation																			172,500,000
Gross proceeds																				$ 172,500,000
Common Class A
Summary of Significant Accounting Policies (Details) [Line Items]
Exercise price per share (in dollars per share) | $ / shares				$ 11.50						$ 11.50										$ 11.50
FocalPoint Securities, LLC
Summary of Significant Accounting Policies (Details) [Line Items]
Fair value of deferred payments																			22,661,000
Lingo
Summary of Significant Accounting Policies (Details) [Line Items]
Equity interest in acquiree, percentage																						80.00%	40.00%			40.00%
Equity interests issued and issuable																			4,408,000
Converted instrument, amount																			17,500,000
Secured Debt | Term Loan | Line of Credit
Summary of Significant Accounting Policies (Details) [Line Items]
Principal amount	$ 148,200,000
W.S. Badcock Corporation
Summary of Significant Accounting Policies (Details) [Line Items]
Total assets measured at fair value				$ 400,000,000		318,109,000				$ 400,000,000				318,109,000					318,109,000	$ 400,000,000
Payments to acquire finance receivables	168,363,000																			400,000,000
Receivable with imputed interest, face amount	$ 168,363,000					400,000								400,000					400,000
Loans receivable, at fair value				$ 400,000,000		$ 318,109,000				$ 400,000,000				$ 318,109,000					$ 318,109,000	$ 400,000,000
Lingo
Summary of Significant Accounting Policies (Details) [Line Items]
Fair value of noncontrolling interest (in percentage)																						20.00%
Bebe Stores Inc. ("bebe")
Summary of Significant Accounting Policies (Details) [Line Items]
Ownership, percentage				40.10%		40.10%				40.10%				40.10%					40.10%	40.10%				40.10%
Additional purchase of shares (in shares) | shares				71,970
National Holdings Corporation
Summary of Significant Accounting Policies (Details) [Line Items]
Ownership, percentage																					45.00%				55.00%
Equity investments
Summary of Significant Accounting Policies (Details) [Line Items]
Operating lease right-of-use assets				$ 18,862,000		$ 48,552,000				$ 18,862,000				$ 48,552,000					$ 48,552,000	$ 18,862,000	$ 8,915,000
Operating lease liabilities				20,137,000		49,050,000				20,137,000				49,050,000					49,050,000	20,137,000	8,915,000
Fixed Income Securities
Summary of Significant Accounting Policies (Details) [Line Items]
Interest expense																			66,495,000	51,753,000	40,490,000
Forward Contracts
Summary of Significant Accounting Policies (Details) [Line Items]
Net gain (loss) forward exchange contract																			68,000	1,052,000	$ 285,000
2018 Employee Stock Purchase Plan
Summary of Significant Accounting Policies (Details) [Line Items]
Market value percentage					85.00%
Warrant
Summary of Significant Accounting Policies (Details) [Line Items]
Warrant liability				$ 12,938,000		173,000				$ 12,938,000				173,000					173,000	$ 12,938,000
IPO
Summary of Significant Accounting Policies (Details) [Line Items]
Consummated units (in shares) | shares																				17,250,000
IPO | Common Class A
Summary of Significant Accounting Policies (Details) [Line Items]
Class of warrant or right, number of securities called by each warrant or right (in shares) | shares				1						1										1				1
Fair Value, Measurements, Recurring
Summary of Significant Accounting Policies (Details) [Line Items]
Loans receivable carrying value				$ 877,527,000		769,022,000				$ 877,527,000				769,022,000					769,022,000	$ 877,527,000
Loans receivable				886,831,000		772,873,000				886,831,000				772,873,000					772,873,000	886,831,000
Total assets measured at fair value				$ 1,250,735,000		1,070,117,000				$ 1,250,735,000				1,070,117,000					$ 1,070,117,000	$ 1,250,735,000
Maximum
Summary of Significant Accounting Policies (Details) [Line Items]
Cash fee percentage																			10.00%
Carried interest percentage																			15.00%
Maximum | Bebe Stores Inc. ("bebe")
Summary of Significant Accounting Policies (Details) [Line Items]
Ownership, percentage				39.50%						39.50%										39.50%				39.50%
Minimum
Summary of Significant Accounting Policies (Details) [Line Items]
Cash fee percentage																			7.00%
Carried interest percentage																			8.00%
Minimum | Bebe Stores Inc. ("bebe")
Summary of Significant Accounting Policies (Details) [Line Items]
Ownership, percentage				40.10%						40.10%										40.10%				40.10%
Fair Value, Inputs, Level 3
Summary of Significant Accounting Policies (Details) [Line Items]
Total assets measured at fair value				$ 873,186,000		701,652,000				$ 873,186,000				701,652,000					$ 701,652,000	$ 873,186,000
Loans receivable, at fair value				873,186,000		701,652,000				873,186,000				701,652,000					701,652,000	873,186,000
Total assets measured at fair value				1,250,735,000		1,070,117,000				1,250,735,000				1,070,117,000					1,070,117,000	1,250,735,000
Warrant liability				$ 0		$ 0				$ 0				$ 0					$ 0	$ 0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Summary of Significant Accounting Policies (Details) [Line Items]
Percentage of total assets measured in Level 3 of the hierarchy level				21.40%		17.50%				21.40%				17.50%					17.50%	21.40%				21.40%
BR Brands Warrants
Summary of Significant Accounting Policies (Details) [Line Items]
Warrants repurchased (in shares) | shares																											200,000
Exercise price (in dollars per share) | $ / shares																											$ 26.24
Class of warrant or right, outstanding (in shares) | shares						200,000								200,000					200,000
BR Brands Warrants First
Summary of Significant Accounting Policies (Details) [Line Items]
Class of warrant or right, vesting ratio																											33.33%
BR Brands Warrants Second
Summary of Significant Accounting Policies (Details) [Line Items]
Class of warrant or right, vesting ratio																											66.67%
Issued for Sale of Equity Securities
Summary of Significant Accounting Policies (Details) [Line Items]
Notes issued																				$ 200,000
Note 1 Issued for Sale of Equity Securities
Summary of Significant Accounting Policies (Details) [Line Items]
Notes issued																				$ 51,000,000