Capital Ratios (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2015
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital Conservation Buffer	2.50%		0.625%
Park National Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Leverage Capital to Average Assets	8.62%	8.29%
Tier One Risk Based Capital to Risk Weighted Assets	11.05%	11.01%
Common Equity Tier 1	11.05%	11.01%
Capital to Risk Weighted Assets	12.25%	12.30%
Leverage Capital Required For Capital Adequacy To Average Total Assets	4.00%	4.00%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Common Equity Tier 1 Capital Required For Capital Adequacy To Average Total Assets	4.50%	4.50%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Leverage Capital Required To Be Well Capitalized To Average Total Assets	5.00%	5.00%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%
Common Equity Tier 1 Capital Required To Be Well Capitalized To Average Total Assets	6.50%	6.50%
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%
Risk Based Capital	$ 810,880	$ 709,101
Capital Required for Capital Adequacy	529,480	461,293
Capital Required to be Well Capitalized	661,850	576,617
Tier One Risk Based Capital	731,071	634,909
Tier One Risk Based Capital Required for Capital Adequacy	397,110	345,970
Tier One Risk Based Capital Required to be Well Capitalized	529,480	461,293
Tier One Leverage Capital	731,071	634,909
Tier One Leverage Capital Required for Capital Adequacy	339,092	306,485
Tier One Leverage Capital Required to be Well Capitalized	423,866	383,106
Common Equity Tier One Capital	731,071	634,909
Common Equity Tier One Capital Required for Capital Adequacy	297,832	259,478
Common Equity Tier One Capital Required to be Well-Capitalized	$ 430,202	$ 374,801
Park
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Leverage Capital to Average Assets	9.64%	10.04%
Tier One Risk Based Capital to Risk Weighted Assets	12.33%	13.30%
Common Equity Tier 1	12.11%	13.04%
Capital to Risk Weighted Assets	13.19%	14.19%
Leverage Capital Required For Capital Adequacy To Average Total Assets	4.00%	4.00%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Common Equity Tier 1 Capital Required For Capital Adequacy To Average Total Assets	4.50%	4.50%
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Leverage Capital Required For Capital Adequacy plus capital conservation buffer To Average Total Assets	4.00%	4.00%
Tier One Risk Based Capital Required For Capital Adequacy plus capital conservation buffer To Average Total Assets	8.50%	8.50%
Common Equity Tier 1 Capital Required For Capital Adequacy plus capital conservation buffer To Average Total Assets	7.00%	7.00%
Capital Required For Capital Adequacy plus capital conservation buffer To Average Total Assets	10.50%	10.50%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.00%	6.00%
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%
Risk Based Capital	$ 877,108	$ 826,006
Capital Required for Capital Adequacy	532,169	465,732
Capital Required to be Well Capitalized	665,211	582,166
Tier One Risk Based Capital	820,312	774,369
Tier One Risk Based Capital Required for Capital Adequacy	399,127	349,299
Tier One Risk Based Capital Required to be Well Capitalized	399,127	349,299
Tier One Leverage Capital	820,312	774,369
Tier One Leverage Capital Required for Capital Adequacy	340,412	308,397
Common Equity Tier One Capital	805,312	759,369
Common Equity Tier One Capital Required for Capital Adequacy	$ 299,345	$ 261,975

Capital Conservation Buffer

No definition available.

Name:	prk_CapitalConservationBuffer
Namespace Prefix:	prk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Capital Required For Capital Adequacy plus capital conservation buffer To Average Total Assets

+ References

No definition available.

+ Details

Name:	prk_CapitalRequiredForCapitalAdequacypluscapitalconservationbufferToAverageTotalAssets
Namespace Prefix:	prk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Equity Tier 1 Capital Required For Capital Adequacy To Average Total Assets

+ References

No definition available.

+ Details

Name:	prk_CommonEquityTier1CapitalRequiredForCapitalAdequacyToAverageTotalAssets
Namespace Prefix:	prk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Equity Tier 1 Capital Required For Capital Adequacy plus capital conservation buffer To Average Total Assets

+ References

No definition available.

+ Details

Name:	prk_CommonEquityTier1CapitalRequiredForCapitalAdequacypluscapitalconservationbufferToAverageTotalAssets
Namespace Prefix:	prk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Equity Tier 1 Capital Required To Be Well Capitalized To Average Total Assets

+ References

No definition available.

+ Details

Name:	prk_CommonEquityTier1CapitalRequiredToBeWellCapitalizedToAverageTotalAssets
Namespace Prefix:	prk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Leverage Capital Required For Capital Adequacy plus capital conservation buffer To Average Total Assets

+ References

No definition available.

+ Details

Name:	prk_LeverageCapitalRequiredForCapitalAdequacypluscapitalconservationbufferToAverageTotalAssets
Namespace Prefix:	prk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Risk Based Capital

+ References

No definition available.

+ Details

Name:	prk_RiskBasedCapital
Namespace Prefix:	prk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Tier One Risk Based Capital Required For Capital Adequacy plus capital conservation buffer To Average Total Assets

+ References

No definition available.

+ Details

Name:	prk_TierOneRiskBasedCapitalRequiredForCapitalAdequacypluscapitalconservationbufferToAverageTotalAssets
Namespace Prefix:	prk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1H
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

+ Details

Name:	us-gaap_CapitalRequiredToBeWellCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Total Capital divided by risk weighted assets as defined in the regulations.

+ References

+ Details

Name:	us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of Common Equity Tier One Risk-based Capital, as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

+ Details

Name:	us-gaap_CommonEquityTierOneCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of Common Equity Tier One Risk-based Capital to total risk-weighted assets, as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_CommonEquityTierOneCapitalRatio
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of Common Equity Tier 1 Risk-based Capital required to be categorized as adequately capitalized under regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of Common Equity Tier 1 Risk-based Capital required to be categorized as well-capitalized under regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CommonEquityTierOneCapitalRequiredToBeWellCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

+ Details

Name:	us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1H
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier 1 Leverage Capital divided by average assets as defined in the regulations.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier 1 Risk Based Capital as defined in the regulations.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1H
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=d3e65071-112826

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier 1 capital divided by risk weighted assets as defined by regulations.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=prk_ParkNationalBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=prk_ParkMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: