Fair value measurements - Notional Amounts and Fair Values of Derivatives by Product (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Derivative asset, Notional	$ 360	$ 8,700
Derivatives asset, Fair Value	0	13
Derivative liability, notional	11,475,360	6,878,700
Derivative liability, Fair Value	1,071	737
Other contracts \| TBAs
Derivatives, Fair Value [Line Items]
Derivative asset, Notional	360	3,700
Derivatives asset, Fair Value	0	11
Derivative liability, notional	360	3,700
Derivative liability, Fair Value	0	2
Commodity contracts \| Futures
Derivatives, Fair Value [Line Items]
Derivative asset, Notional		5,000
Derivatives asset, Fair Value		2
Derivative liability, notional	11,475,000	6,875,000
Derivative liability, Fair Value	$ 1,071	$ 735

Nominal or face amount used to calculate payments on the derivative asset.

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Nominal or face amount used to calculate payments on the derivative liability.

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