Variable interest entities and securitization activities - Assets of Unconsolidated VIEs (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Carrying amount
Mortgage-backed securities	$ 30,174	$ 27,436
Investment in unconsolidated joint ventures	134,602	133,321
Total Assets	11,774,333	12,441,217
Unconsolidated VIEs
Carrying amount
Mortgage-backed securities	27,364	26,301
Investment in unconsolidated joint ventures	134,602	133,321
Total Assets	161,966	159,622
Maximum Exposure to Loss
Mortgage backed securities, at fair value	27,364	26,301
Investment in unconsolidated joint venture	134,602	133,321
Total assets in unconsolidated VIEs maximum exposure to loss	$ 161,966	$ 159,622