Bank segment - Credit risk profile - summary (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Credit risk profile based on nonaccrual loans
Nonaccrual loans	$ 40,207	$ 27,295
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	25,356	25,917
Residential 1-4 family
Credit risk profile based on nonaccrual loans
Nonaccrual loans	13,878	12,037
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	10,145	10,194
Commercial real estate
Credit risk profile based on nonaccrual loans
Nonaccrual loans	0	0
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	902	915
Home equity line of credit
Credit risk profile based on nonaccrual loans
Nonaccrual loans	6,888	6,348
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	11,013	11,597
Residential land
Credit risk profile based on nonaccrual loans
Nonaccrual loans	452	436
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	1,613	1,622
Commercial construction
Credit risk profile based on nonaccrual loans
Nonaccrual loans	0	0
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	0	0
Residential construction
Credit risk profile based on nonaccrual loans
Nonaccrual loans	0	0
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	0	0
Commercial loans
Credit risk profile based on nonaccrual loans
Nonaccrual loans	14,447	4,278
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	1,622	1,527
Consumer loans
Credit risk profile based on nonaccrual loans
Nonaccrual loans	4,542	4,196
Accruing loans 90 days or more past due	0	0
Total troubled debt restructuring loans not included above	$ 61	$ 62

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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+ References

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