Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2018
Accounting Policies [Abstract]
Stock Dividend	*Stock Dividend* On July 1, 2017, the Company paid a special stock dividend of four percent to shareholders of record at the close of business on June 15, 2017. For all periods presented, share information, including basic and diluted earnings per share, has been adjusted retroactively to reflect this change.
New accounting principles adopted in 2018	The following represents significant new accounting principles adopted in 2018: *Revenue from Contracts with Customers* On January 1, 2018, the Company adopted ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) and all subsequent ASUs that modified Topic 606. The implementation of the new standard did not have a material impact on the measurement or recognition of revenue; as such, a cumulative effect adjustment to opening retained earnings was not deemed necessary. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts were not adjusted and continue to be reported in accordance with historic accounting under Topic 605. Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain noninterest income streams such as fees associated with mortgage servicing rights, financial guarantees, derivatives, and certain credit card fees are also not in scope of the new guidance. Topic 606 is applicable to noninterest revenue streams such as trust department revenue, service charges and fees, debit card income, ATM surcharge income, and other real estate owned sales. However, the recognition of these revenue streams did not change significantly upon adoption of Topic 606. Noninterest revenue streams within the scope of Topic 606 are discussed in Footnote 16. *Financial Instruments* The FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, in January 2016. The amendments require all equity investments to be measured at fair value with changes in the fair value recognized through net income, other than those accounted for under the equity method of accounting or those that result in the consolidation of the investee. Additionally, these amendments require presentation in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk for those liabilities measured at fair value. The amendments also require use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes. These amendments are effective for interim and annual periods beginning January 1, 2018. The adoption of the ASU's did not have a significant effect on the Company's consolidated financial statements. The FASB issued ASU 2018-04, Investments - Debt Securities (Topic 320) and Regulated Operations (Topic 980): The amendment in this ASU adds, amends and supersedes various paragraphs that contain SEC guidance in ASC 320, Investments-Debt Securities and ASC 980, Regulated Operations. The amendments in this ASU are effective when a registrant adopts ASU 2016-01, which for the Company was January 1, 2018. This amendment did not have a significant effect on the Company's consolidated financial statements. *Liabilities* The FASB issued ASU 2016-04, Recognition of Breakage for Certain Prepaid Store-Value Products, in March 2016, in order to address current and potential future diversity in practice related to the derecognition of a prepaid store-value product liability. Such products include prepaid gift cards issued on a specific payment network and redeemable at network-accepting merchant locations, prepaid telecommunication cards, and traveler's checks. The amendments require that the portion of the dollar value of prepaid stored-value products that is ultimately unredeemed (that is, the breakage) be accounted for consistent with the breakage guidance for stored-value product transactions provided in ASC Topic 606 - Revenue from Contracts with Customers. These amendments are effective for interim and annual periods beginning January 1, 2018. The adoption of the ASU's did not have a significant effect on the Company's consolidated financial statements. *Pension* The FASB issued ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost in March 2017. Under the new guidance, employers will present the service cost component of the net periodic benefit cost in the same income statement line item (e.g., Salaries and Benefits) as other employee compensation costs arising from services rendered during the period. In addition, only the service cost component will be eligible for capitalization in assets. Employers will present the other components separately (e.g., Other Noninterest Expense) from the line item that includes the service cost. The ASU is effective for interim and annual reporting periods beginning after December 15, 2017. Early adoption is permitted, however, the Company has decided not to early adopt. Employers will apply the guidance on the presentation of the components of net periodic benefit cost in the income statement retrospectively. The guidance limiting the capitalization of net periodic benefit cost in assets to the service cost component will be applied prospectively. The Company expects to utilize the ASU’s practical expedient allowing entities to estimate amounts for comparative periods using the information previously disclosed in their pension and other postretirement benefit plan footnote. The adoption of the ASU's did not have a significant effect on the Company's consolidated financial statements.

The following represents significant new accounting principles adopted in 2018:

Revenue from Contracts with Customers On January 1, 2018, the Company adopted ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) and all subsequent ASUs that modified Topic 606. The implementation of the new standard did not have a material impact on the measurement or recognition of revenue; as such, a cumulative effect adjustment to opening retained earnings was not deemed necessary. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts were not adjusted and continue to be reported in accordance with historic accounting under Topic 605.

Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain noninterest income streams such as fees associated with mortgage servicing rights, financial guarantees, derivatives, and certain credit card fees are also not in scope of the new guidance. Topic 606 is applicable to noninterest revenue streams such as trust department revenue, service charges and fees, debit card income, ATM surcharge income, and other real estate owned sales. However, the recognition of these revenue streams did not change significantly upon adoption of Topic 606. Noninterest revenue streams within the scope of Topic 606 are discussed in Footnote 16.

Financial Instruments The FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, in January 2016. The amendments require all equity investments to be measured at fair value with changes in the fair value recognized through net income, other than those accounted for under the equity method of accounting or those that result in the consolidation of the investee. Additionally, these amendments require presentation in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk for those liabilities measured at fair value. The amendments also require use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes. These amendments are effective for interim and annual periods beginning January 1, 2018. The adoption of the ASU's did not have a significant effect on the Company's consolidated financial statements.

The FASB issued ASU 2018-04, Investments - Debt Securities (Topic 320) and Regulated Operations (Topic 980): The amendment in this ASU adds, amends and supersedes various paragraphs that contain SEC guidance in ASC 320, Investments-Debt Securities and ASC 980, Regulated Operations. The amendments in this ASU are effective when a registrant adopts ASU 2016-01, which for the Company was January 1, 2018. This amendment did not have a significant effect on the Company's consolidated financial statements.

Liabilities The FASB issued ASU 2016-04, Recognition of Breakage for Certain Prepaid Store-Value Products, in March 2016, in order to address current and potential future diversity in practice related to the derecognition of a prepaid store-value product liability. Such products include prepaid gift cards issued on a specific payment network and redeemable at network-accepting merchant locations, prepaid telecommunication cards, and traveler's checks. The amendments require that the portion of the dollar value of prepaid stored-value products that is ultimately unredeemed (that is, the breakage) be accounted for consistent with the breakage guidance for stored-value product transactions provided in ASC Topic 606 - Revenue from Contracts with Customers. These amendments are effective for interim and annual periods beginning January 1, 2018. The adoption of the ASU's did not have a significant effect on the Company's consolidated financial statements.

Pension The FASB issued ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost in March 2017. Under the new guidance, employers will present the service cost component of the net periodic benefit cost in the same income statement line item (e.g., Salaries and Benefits) as other employee compensation costs arising from services rendered during the period. In addition, only the service cost component will be eligible for capitalization in assets. Employers will present the other components separately (e.g., Other Noninterest Expense) from the line item that includes the service cost. The ASU is effective for interim and annual reporting periods beginning after December 15, 2017. Early adoption is permitted, however, the Company has decided not to early adopt. Employers will apply the guidance on the presentation of the components of net periodic benefit cost in the income statement retrospectively. The guidance limiting the capitalization of net periodic benefit cost in assets to the service cost component will be applied prospectively. The Company expects to utilize the ASU’s practical expedient allowing entities to estimate amounts for comparative periods using the information previously disclosed in their pension and other postretirement benefit plan footnote. The adoption of the ASU's did not have a significant effect on the Company's consolidated financial statements.