Bank segment - Derivatives (Details) - Derivative Financial Instruments Not Designated as Hedging Instruments - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Derivative instrument
Asset derivatives	$ 429		$ 429		$ 4,536
Liability derivatives	12		12		500
Net gains (losses) recognized in the Statement of Income	87	$ 2,974	(3,619)	$ 4,773
Interest rate lock commitments
Derivative instrument
Notional amount	22,289		22,289		120,980
Fair value	308		308		4,536
Asset derivatives	308		308		4,536
Liability derivatives	0		0		0
Interest rate lock commitments \| Mortgage banking income
Derivative instrument
Net gains (losses) recognized in the Statement of Income	(63)	2,930	(4,228)	4,974
Forward commitments
Derivative instrument
Notional amount	21,750		21,750		100,500
Fair value	109		109		(500)
Asset derivatives	121		121		0
Liability derivatives	12		12		$ 500
Forward commitments \| Mortgage banking income
Derivative instrument
Net gains (losses) recognized in the Statement of Income	$ 150	$ 44	$ 609	$ (201)

Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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