Bank segment - Loan modifications (Details) - Troubled debt restructurings real estate loans $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020 USD ($) contract	Sep. 30, 2019 USD ($) contract	Sep. 30, 2020 USD ($) contract	Sep. 30, 2019 USD ($) contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	2	5	12	22
Outstanding recorded investment	$ 52	$ 949	$ 16,752	$ 4,922
Related allowance	$ 45	$ 58	$ 4,222	$ 468
Real estate \| Residential 1-4 family
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	0	1	1	10
Outstanding recorded investment	$ 0	$ 324	$ 146	$ 1,563
Related allowance	$ 0	$ 0	$ 7	$ 165
Real estate \| Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	0	0	2	0
Outstanding recorded investment	$ 0	$ 0	$ 16,149	$ 0
Related allowance	$ 0	$ 0	$ 4,019	$ 0
Real estate \| Home equity line of credit
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	0	0	2	3
Outstanding recorded investment	$ 0	$ 0	$ 22	$ 429
Related allowance	$ 0	$ 0	$ 1	$ 85
Real estate \| Residential land
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	0	1	2	3
Outstanding recorded investment	$ 0	$ 350	$ 228	$ 1,169
Related allowance	$ 0	$ 0	$ 15	$ 0
Real estate \| Commercial construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	0	0	0	0
Outstanding recorded investment	$ 0	$ 0	$ 0	$ 0
Related allowance	$ 0	$ 0	$ 0	$ 0
Real estate \| Residential construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	0	0	0	0
Outstanding recorded investment	$ 0	$ 0	$ 0	$ 0
Related allowance	$ 0	$ 0	$ 0	$ 0
Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	2	3	5	6
Outstanding recorded investment	$ 52	$ 275	$ 207	$ 1,761
Related allowance	$ 45	$ 58	$ 180	$ 218
Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of contracts \| contract	0	0	0	0
Outstanding recorded investment	$ 0	$ 0	$ 0	$ 0
Related allowance	$ 0	$ 0	$ 0	$ 0

Amount of increase (decrease) of allowance reserve for credit loss.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

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