Variable interest entities ("VIEs") (Details) $ in Thousands	Mar. 31, 2024 USD ($) company	Dec. 31, 2023 USD ($)	Mar. 31, 2023 USD ($)
Variable Interest Entity [Line Items]
Number of special purpose acquisition companies | company	2
Cash and cash equivalents	$ 27,661	$ 28,835	$ 30,320
Restricted Cash	0		25,581
Other Assets	119,968	101,775
Total assets	3,251,890	2,874,816
Total liabilities	2,450,368	$ 2,085,577
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	11		5,810
Restricted Cash	0		25,581
Other Assets	0		730
Total assets	11		32,121
Other Liabilities	171		859
Total liabilities	$ 171		$ 859