Fair Value Measurements - Quantitative inputs and assumptions for Level 3 financial instruments carried at fair value on nonrecurring basis (Details) $ in Thousands	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other real estate owned	$ 1,217	$ 0
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other real estate owned	1,217
Servicing liability	68	73
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other real estate owned	1,217
Servicing liability	68	73
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other real estate owned	1,217
Servicing liability	68	73
Fair Value Measurements Nonrecurring \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impaired loans	14,847	18,709
Other real estate owned	1,217
Servicing asset, net	776	797
Fair Value Measurements Nonrecurring \| Level 3 \| Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impaired loans	14,847	18,709
Servicing asset, net	$ 776	$ 797
Fair Value Measurements Nonrecurring \| Level 3 \| Discount rate \| Fair Value \| Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Servicing liability, measurement input (percent)	0.019	0.028
Fair Value Measurements Nonrecurring \| Level 3 \| Discount rate \| Fair Value \| Minimum \| Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Servicing asset, measurement input (percent)	0.1000	0.1000
Fair Value Measurements Nonrecurring \| Level 3 \| Discount rate \| Fair Value \| Maximum \| Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Servicing asset, measurement input (percent)	0.1150	0.1200
Fair Value Measurements Nonrecurring \| Level 3 \| Prepayment rate \| Fair Value \| Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Servicing asset, measurement input (percent)	0.0300	0.0300
Fair Value Measurements Nonrecurring \| Level 3 \| Prepayment rate \| Fair Value \| Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Servicing asset, measurement input (percent)	0.1715	0.1500
Fair Value Measurements Nonrecurring \| Level 3 \| Impaired loans \| Fair Value \| Appraisals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impaired loans	$ 7,779	$ 10,188
Other real estate owned	1,217
Fair Value Measurements Nonrecurring \| Level 3 \| Impaired loans \| Fair Value \| Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impaired loans	$ 7,068	$ 8,521
Fair Value Measurements Nonrecurring \| Level 3 \| Impaired loans \| Appraised value \| Appraisals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Other real estate, measurement input (percent)		0.3800
Fair Value Measurements Nonrecurring \| Level 3 \| Impaired loans \| Appraised value \| Minimum \| Appraisals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impaired loan, measurement input (percent)	0.0000	0.0500
Fair Value Measurements Nonrecurring \| Level 3 \| Impaired loans \| Appraised value \| Maximum \| Appraisals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impaired loan, measurement input (percent)	0.2800	0.0800
Fair Value Measurements Nonrecurring \| Level 3 \| Impaired loans \| Discount rate \| Minimum \| Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impaired loan, measurement input (percent)	0.0360	0.0325
Fair Value Measurements Nonrecurring \| Level 3 \| Impaired loans \| Discount rate \| Maximum \| Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impaired loan, measurement input (percent)	0.0800	0.0800

Represent fair value of impaired loan.

No definition available.

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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

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
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

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))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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- Definition

Value of input used to measure real estate owned by financial institution by financial institution which is not directly related to its business.

+ References

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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

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- Definition

Value of input used to measure servicing asset.

+ References

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- Definition

Aggregate amount of servicing liabilities that are subsequently measured at fair value and servicing liabilities that are subsequently measured using the amortization method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

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- Definition

Value of input used to measure servicing liability.

+ References

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