Fair Value - Assets and liabilities measured at fair value on a nonrecurring basis (Details) - Nonrecurring basis $ in Thousands	Dec. 31, 2020 USD ($) item	Dec. 31, 2019 USD ($) item
OREO \| Fair Value
Fair Value
Other Real Estate	$ 11,914	$ 6,539
Bank property held for sale \| Fair Value
Fair Value
Bank property held for sale	36,006	5,425
Non-acquired impaired loans \| Fair Value
Fair Value
Other Real Estate	$ 17,609	$ 15,444
Significant Unobservable Inputs (Level 3) \| Impaired loans
Quantitative Information about Level 3 Fair Value Measurements
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Significant Unobservable Inputs (Level 3) \| Impaired loans \| Weighted average
Quantitative Information about Level 3 Fair Value Measurements
Discount rate (as a percent) \| item	0.05	0.02
Significant Unobservable Inputs (Level 3) \| OREO
Fair Value
Other Real Estate	$ 11,914	$ 6,539
Quantitative Information about Level 3 Fair Value Measurements
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Significant Unobservable Inputs (Level 3) \| OREO \| Weighted average
Quantitative Information about Level 3 Fair Value Measurements
Discount rate (as a percent) \| item	0.14	0.31
Significant Unobservable Inputs (Level 3) \| Bank property held for sale
Fair Value
Bank property held for sale	$ 36,006	$ 5,425
Significant Unobservable Inputs (Level 3) \| Non-acquired impaired loans
Fair Value
Other Real Estate	$ 17,609	$ 15,444

Fair value portion of assets classified as held for sale.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- Definition

Value of input used to measure long-term debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
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-Paragraph 2
-Subparagraph (bbb)(1)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Carrying amount of other real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This does not include real estate assets taken in settlement of troubled loans through surrender or foreclosure.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
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