Adoption of New Accounting Pronouncements (Notes)	12 Months Ended
Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Adoption of New Accounting Pronouncements and Issued Not Yet Effective Accounting Standards ASU 2014-09 - Revenue from Contracts with Customers (Topic 606): In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). The ASU creates a new topic, Topic 606, to provide guidance on revenue recognition for entities that enter into contracts with customers to transfer goods or services or enter into contracts for the transfer of nonfinancial assets. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Additional disclosures are required to provide quantitative and qualitative information regarding the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2017. While interest income is specifically out of scope of this standard, management is currently evaluating the revenue streams within "Other income" to assess the applicability of this standard. Specifically, management is evaluating the impact of this new guidance on deposit fees recorded within "Service Charges on Deposit Accounts" and trust income within "Income from Fiduciary Activities." ASU 2015-02 - Consolidation (Topic 810): Amendments to the Consolidation Analysis: In February 2015, the FASB issued ASU 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis. The ASU amends the current consolidation guidance and affect both the variable interest entity and voting interest entity consolidation models. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2015. The adoption of this guidance on January 1, 2016 did not have an impact on Park’s consolidated financial statements. ASU 2016-01 - Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. In January 2016, the FASB issued ASU 2016-01 - Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. Changes to the current U.S. GAAP model primarily affect the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the ASU clarifies guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale securities. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2017. The adoption of this guidance is not expected to have a material impact on Park's consolidated financial statements. ASU 2016-02 - Leases (Topic 842): In February 2016, the FASB issued ASU 2016-02 - Leases (Topic 842). The ASU will require all organizations that lease assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. Additional qualitative and quantitative disclosures will be required so that users can understand more about the nature of an entity’s leasing activities. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2018. Early adoption is permitted. Management is currently analyzing data on leased assets. The adoption of this guidance is expected to increase both assets and liabilities, but is not expected to have a material impact on Park's consolidated statement of income. ASU 2016-09 - Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting: In March 2016, FASB issued ASU 2016-09 - Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The ASU provides simplification for several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2016. Early adoption was permitted. The adoption of this guidance on January 1, 2017 did not have a material impact on Park's consolidated financial statements. ASU 2016-13 - Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments: In June 2016, FASB issued ASU 2016-13 - Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The new guidance replaces the incurred loss model with an expected loss model, which is referred to as the current expected credit loss ("CECL") model. The CECL model is applicable to the measurement of credit losses on financial assets measured at amortized cost, including loan receivables, HTM debt securities, and reinsurance receivables. It also applies to off-balance sheet credit exposures not accounted for as insurance (loan commitments, standby letters of credit, financial guarantees, and other similar instruments) and net investments in leases recognized by a lessor. The CECL model requires an entity to estimate the credit losses over the life of an asset or off-balance sheet exposure. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2018. Management is currently evaluating the impact of the adoption of this guidance on Park's consolidated financial statements. We anticipate that the adoption of the CECL model will result in a material increase to Park's allowance for loan losses. Management has established a committee to oversee the implementation of CECL. This committee is currently assessing the data and system requirements necessary for adoption. Management plans to run our current model and a CECL model concurrently for 12 months prior to the adoption of this guidance on January 1, 2020. ASU 2016-15 - Statement of Cash Flows (Topic 203): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force): In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 203): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force). This ASU provides guidance on eight specific cash flow issues where current GAAP is either unclear or does not include specific guidance. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2017. As such transactions arise, management will utilize the updated guidance within Park’s consolidated statements of cash flows. ASU 2017-04 - Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment: In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This ASU eliminates Step 2 from the goodwill impairment test. Instead, under the new guidance, an entity should perform its annual goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge would be recognized for the amount by which the carrying amount exceeds the reporting unit's fair value. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this guidance is not expected to have an impact on Park's consolidated financial statements.

Adoption of New Accounting Pronouncements and Issued Not Yet Effective Accounting Standards

ASU 2014-09 - Revenue from Contracts with Customers (Topic 606): In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). The ASU creates a new topic, Topic 606, to provide guidance on revenue recognition for entities that enter into contracts with customers to transfer goods or services or enter into contracts for the transfer of nonfinancial assets. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Additional disclosures are required to provide quantitative and qualitative information regarding the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2017. While interest income is specifically out of scope of this standard, management is currently evaluating the revenue streams within "Other income" to assess the applicability of this standard. Specifically, management is evaluating the impact of this new guidance on deposit fees recorded within "Service Charges on Deposit Accounts" and trust income within "Income from Fiduciary Activities."

ASU 2015-02 - Consolidation (Topic 810): Amendments to the Consolidation Analysis: In February 2015, the FASB issued ASU 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis. The ASU amends the current consolidation guidance and affect both the variable interest entity and voting interest entity consolidation models. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2015. The adoption of this guidance on January 1, 2016 did not have an impact on Park’s consolidated financial statements.

ASU 2016-01 - Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. In January 2016, the FASB issued ASU 2016-01 - Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. Changes to the current U.S. GAAP model primarily affect the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the ASU clarifies guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale securities. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2017. The adoption of this guidance is not expected to have a material impact on Park's consolidated financial statements.

ASU 2016-02 - Leases (Topic 842): In February 2016, the FASB issued ASU 2016-02 - Leases (Topic 842). The ASU will require all organizations that lease assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. Additional qualitative and quantitative disclosures will be required so that users can understand more about the nature of an entity’s leasing activities. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2018. Early adoption is permitted. Management is currently analyzing data on leased assets. The adoption of this guidance is expected to increase both assets and liabilities, but is not expected to have a material impact on Park's consolidated statement of income.

ASU 2016-09 - Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting: In March 2016, FASB issued ASU 2016-09 - Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The ASU provides simplification for several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2016. Early adoption was permitted. The adoption of this guidance on January 1, 2017 did not have a material impact on Park's consolidated financial statements.

ASU 2016-13 - Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments: In June 2016, FASB issued ASU 2016-13 - Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The new guidance replaces the incurred loss model with an expected loss model, which is referred to as the current expected credit loss ("CECL") model. The CECL model is applicable to the measurement of credit losses on financial assets measured at amortized cost, including loan receivables, HTM debt securities, and reinsurance receivables. It also applies to off-balance sheet credit exposures not accounted for as insurance (loan commitments, standby letters of credit, financial guarantees, and other similar instruments) and net investments in leases recognized by a lessor. The CECL model requires an entity to estimate the credit losses over the life of an asset or off-balance sheet exposure. The new guidance is effective for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted for annual reporting periods and interim reporting periods within those annual periods, beginning after December 15, 2018.

Management is currently evaluating the impact of the adoption of this guidance on Park's consolidated financial statements. We anticipate that the adoption of the CECL model will result in a material increase to Park's allowance for loan losses. Management has established a committee to oversee the implementation of CECL. This committee is currently assessing the data and system requirements necessary for adoption. Management plans to run our current model and a CECL model concurrently for 12 months prior to the adoption of this guidance on January 1, 2020.

ASU 2016-15 - Statement of Cash Flows (Topic 203): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force): In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 203): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force). This ASU provides guidance on eight specific cash flow issues where current GAAP is either unclear or does not include specific guidance. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2017. As such transactions arise, management will utilize the updated guidance within Park’s consolidated statements of cash flows.

ASU 2017-04 - Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment: In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This ASU eliminates Step 2 from the goodwill impairment test. Instead, under the new guidance, an entity should perform its annual goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge would be recognized for the amount by which the carrying amount exceeds the reporting unit's fair value. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this guidance is not expected to have an impact on Park's consolidated financial statements.