Guaranteed loan financing (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Ending balance	$ 814,784	$ 844,540
Guaranteed loan financing
Ending balance	$ 814,784	$ 844,540
Guaranteed loan financing \| Weighted Average
Interest Rates	9.17%	9.17%
Guaranteed loan financing \| Minimum
Interest Rates	1.45%	1.45%
Guaranteed loan financing \| Maximum
Interest Rates	10.50%	10.50%

Carrying value as of the balance sheet date of the sum of the obligations to contract holders to provide to them an agreed upon rate of return pursuant to the terms of the underlying contract. These contracts represent lending by the contract holders to the entity in return for a guaranteed (primarily fixed) interest rate until maturity, unless called earlier if the contracts provide that option to the contract holders (usually institutions). There is little or no insurance risk for the entity.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

Name:	us-gaap_BorrowingsUnderGuaranteedInvestmentAgreements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant