Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The accompanying unaudited consolidated financial statements include 1^ST Constitution Bancorp (the “Company”), its wholly-owned subsidiary, 1^ST Constitution Bank (the “Bank”), and the Bank’s wholly-owned subsidiaries, 1^ST Constitution Investment Company of New Jersey, Inc., FCB Assets Holdings, Inc., 204 South Newman Street Corp. and 249 New York Avenue, LLC. 1^ST Constitution Capital Trust II, a subsidiary of the Company, is not included in the Company’s consolidated financial statements, as it is a variable interest entity and the Company is not the primary beneficiary. All significant intercompany accounts and transactions have been eliminated in consolidation and certain prior period amounts have been reclassified to conform to current year presentation. The accounting and reporting policies of the Company and its subsidiaries conform to accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information and footnote disclosures normally included in financial statements have been condensed or omitted pursuant to such rules and regulations. These consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Form 10-K for the year ended December 31, 2017, filed with the SEC on March 19, 2018. In the opinion of the Company, all adjustments (consisting only of normal recurring accruals) that are necessary for a fair presentation of the operating results for the interim periods have been included. The results of operations for periods of less than a year are not necessarily indicative of results for the full year. The Company has evaluated events and transactions occurring subsequent to the balance sheet date of June 30, 2018 for items that should potentially be recognized or disclosed in these financial statements. The evaluation was conducted through the date these financial statements were issued. Adoption of New Accounting Standards ASU 2014-09 - Revenue from Contracts with Customers (Topic 606) On January 1, 2018, the Company adopted Accounting Standards Update (“ASU”) 2014-09 Revenue from Contracts with Customers and all subsequent amendments to the ASU (collectively, “Topic 606”), which (i) creates a single framework for recognizing revenue from contracts with customers that fall within its scope and (ii) revises when it is appropriate to recognize a gain or loss from the transfer of nonfinancial assets, such as other real estate owned (“OREO”). The majority of the Company’s revenues come from interest income, other services to customers and other sources, including loans, leases and securities that are outside the scope of Topic 606. The Company’s services that fall within the scope of Topic 606 are presented within non-interest income and are recognized as revenue as the Company satisfies its obligation to the customer. Services within the scope of Topic 606 include service charges on deposits, interchange income, other services and the sale of OREO. Refer to Note 6 - Revenue from Contracts with Customers - for further discussion on the Company’s accounting policies for revenue sources within the scope of Topic 606. The Company adopted Topic 606 using the modified retrospective method for reporting periods beginning after January 1, 2018. The Company did not have any contracts that were not completed as of January 1, 2018. The adoption of Topic 606 did not result in a change to the accounting for any of the in-scope revenue streams; therefore, no cumulative effect adjustment was recorded. ASU Update 2017-07 - Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In March 2017, the FASB issued ASU 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” which requires that an employer disaggregate the service cost component from the other components of net benefit costs as follows: (1) service cost must be presented in the same line item(s) as other employee compensation costs. These costs are generally included within income from continuing operations but in some cases, may be eligible for capitalization if certain criteria are met; and (2) all other components of net benefit cost must be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. These generally include interest cost, actual return on plan assets, amortization of prior service cost included in accumulated other comprehensive income and gains or losses from changes in the value of the projected benefit obligation or plan assets. For the Company, the provisions of this ASU are effective for fiscal years beginning after December 15, 2017, including interim periods within those years. The adoption of this guidance in 2018 did not have a material impact on the Company’s consolidated financial statements. ASU Update 2017-01 - Business Combinations (Topic 805): Clarifying the Definition of a Business In January 2017, the FASB issued ASU 2017-01 “Business Combinations (Topic 805): Clarifying the Definition of a Business,” which clarifies the definition of a business with the objective of adding guidance to assist companies and other reporting organizations with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this ASU provide a more robust framework to use in determining when a set of assets and activities is a business. The current definition of a business is interpreted broadly and can be difficult to apply. Stakeholders indicated that analyzing transactions is inefficient and costly and the definition does not permit the use of reasonable judgment. Under current implementation guidance, there are three elements of a business: inputs, processes and outputs. While an integrated set of assets and activities (collectively referred to as a “set”) that is a business usually has outputs, outputs are not required to be present. Additionally, all the inputs and processes that a seller uses in operating a set are not required if market participants can acquire the set and continue to produce outputs, for example, by integrating the acquired set with their own inputs and processes. The ASU introduces a “screen” to assist entities in determining when a set should not be considered a business. If substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the set is not considered a business. If the screen is not met, the ASU requires that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output. Further, the ASU removes the evaluation of whether a market participant could replace missing elements (as required under current U.S. GAAP). For the Company, the ASU is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The amendments in this ASU should be applied prospectively on or after the effective date. No disclosures are required at transition. The adoption of this guidance in 2018 did not have a material impact on the Company’s consolidated financial statements. ASU Update 2016-15 - Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. In August 2016, the FASB issued ASU 2016-15 “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” which clarifies whether the following items should be categorized as operating, investing or financing in the statement of cash flows: (1) debt prepayment and extinguishment costs, (2) settlement of zero-coupon debt, (3) settlement of contingent consideration, (4) insurance proceeds, (5) settlement of corporate-owned life insurance (COLI) and bank-owned life insurance (BOLI) policies, (6) distributions from equity method investees, (7) beneficial interests in securitization transactions and (8) receipts and payments with aspects of more than one class of cash flows. For the Company, the provisions of this ASU are effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The Company currently classifies cash flows related to BOLI in accordance with the guidance, and the adoption of this guidance in 2018 did not have a material impact on its consolidated financial statements. ASU Update 2016-01 - Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued ASU 2016-01 “Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities.” The guidance in the ASU, among other things, requires equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income; simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; eliminates the requirement for public business entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; requires an entity to present separately in other comprehensive income, the portion of the change in fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements; and clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities. For the Company, the guidance in this ASU is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The adoption of this guidance in 2018 did not have a material impact on the Company’s consolidated financial statements.

Summary of Significant Accounting Policies

The accompanying unaudited consolidated financial statements include 1^ST Constitution Bancorp (the “Company”), its wholly-owned subsidiary, 1^ST Constitution Bank (the “Bank”), and the Bank’s wholly-owned subsidiaries, 1^ST Constitution Investment Company of New Jersey, Inc., FCB Assets Holdings, Inc., 204 South Newman Street Corp. and 249 New York Avenue, LLC. 1^ST Constitution Capital Trust II, a subsidiary of the Company, is not included in the Company’s consolidated financial statements, as it is a variable interest entity and the Company is not the primary beneficiary. All significant intercompany accounts and transactions have been eliminated in consolidation and certain prior period amounts have been reclassified to conform to current year presentation. The accounting and reporting policies of the Company and its subsidiaries conform to accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information and footnote disclosures normally included in financial statements have been condensed or omitted pursuant to such rules and regulations. These consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Form 10-K for the year ended December 31, 2017, filed with the SEC on March 19, 2018.

In the opinion of the Company, all adjustments (consisting only of normal recurring accruals) that are necessary for a fair presentation of the operating results for the interim periods have been included. The results of operations for periods of less than a year are not necessarily indicative of results for the full year.

The Company has evaluated events and transactions occurring subsequent to the balance sheet date of June 30, 2018 for items that should potentially be recognized or disclosed in these financial statements. The evaluation was conducted through the date these financial statements were issued.

Adoption of New Accounting Standards

ASU 2014-09 - Revenue from Contracts with Customers (Topic 606)

On January 1, 2018, the Company adopted Accounting Standards Update (“ASU”) 2014-09 Revenue from Contracts with Customers and all subsequent amendments to the ASU (collectively, “Topic 606”), which (i) creates a single framework for recognizing revenue from contracts with customers that fall within its scope and (ii) revises when it is appropriate to recognize a gain or loss from the transfer of nonfinancial assets, such as other real estate owned (“OREO”). The majority of the Company’s revenues come from interest income, other services to customers and other sources, including loans, leases and securities that are outside the scope of Topic 606. The Company’s services that fall within the scope of Topic 606 are presented within non-interest income and are recognized as revenue as the Company satisfies its obligation to the customer. Services within the scope of Topic 606 include service charges on deposits, interchange income, other services and the sale of OREO. Refer to Note 6 - Revenue from Contracts with Customers - for further discussion on the Company’s accounting policies for revenue sources within the scope of Topic 606.

The Company adopted Topic 606 using the modified retrospective method for reporting periods beginning after January 1, 2018. The Company did not have any contracts that were not completed as of January 1, 2018. The adoption of Topic 606 did not result in a change to the accounting for any of the in-scope revenue streams; therefore, no cumulative effect adjustment was recorded.

ASU Update 2017-07 - Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

In March 2017, the FASB issued ASU 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” which requires that an employer disaggregate the service cost component from the other components of net benefit costs as follows: (1) service cost must be presented in the same line item(s) as other employee compensation costs. These costs are generally included within income from continuing operations but in some cases, may be eligible for capitalization if certain criteria are met; and (2) all other components of net benefit cost must be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. These generally include interest cost, actual return on plan assets, amortization of prior service cost included in accumulated other comprehensive income and gains or losses from changes in the value of the projected benefit obligation or plan assets.

For the Company, the provisions of this ASU are effective for fiscal years beginning after December 15, 2017, including interim periods within those years. The adoption of this guidance in 2018 did not have a material impact on the Company’s consolidated financial statements.

ASU Update 2017-01 - Business Combinations (Topic 805): Clarifying the Definition of a Business

In January 2017, the FASB issued ASU 2017-01 “Business Combinations (Topic 805): Clarifying the Definition of a Business,” which clarifies the definition of a business with the objective of adding guidance to assist companies and other reporting organizations with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this ASU provide a more robust framework to use in determining when a set of assets and activities is a business. The current definition of a business is interpreted broadly and can be difficult to apply. Stakeholders indicated that analyzing transactions is inefficient and costly and the definition does not permit the use of reasonable judgment.

Under current implementation guidance, there are three elements of a business: inputs, processes and outputs. While an integrated set of assets and activities (collectively referred to as a “set”) that is a business usually has outputs, outputs are not required to be present. Additionally, all the inputs and processes that a seller uses in operating a set are not required if market participants can acquire the set and continue to produce outputs, for example, by integrating the acquired set with their own inputs and processes.

The ASU introduces a “screen” to assist entities in determining when a set should not be considered a business. If substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the set is not considered a business. If the screen is not met, the ASU requires that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output. Further, the ASU removes the evaluation of whether a market participant could replace missing elements (as required under current U.S. GAAP).

For the Company, the ASU is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The amendments in this ASU should be applied prospectively on or after the effective date. No disclosures are required at transition. The adoption of this guidance in 2018 did not have a material impact on the Company’s consolidated financial statements.

ASU Update 2016-15 - Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.

In August 2016, the FASB issued ASU 2016-15 “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” which clarifies whether the following items should be categorized as operating, investing or financing in the statement of cash flows: (1) debt prepayment and extinguishment costs, (2) settlement of zero-coupon debt, (3) settlement of contingent consideration, (4) insurance proceeds, (5) settlement of corporate-owned life insurance (COLI) and bank-owned life insurance (BOLI) policies, (6) distributions from equity method investees, (7) beneficial interests in securitization transactions and (8) receipts and payments with aspects of more than one class of cash flows.

For the Company, the provisions of this ASU are effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The Company currently classifies cash flows related to BOLI in accordance with the guidance, and the adoption of this guidance in 2018 did not have a material impact on its consolidated financial statements.

ASU Update 2016-01 - Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities

In January 2016, the FASB issued ASU 2016-01 “Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities.” The guidance in the ASU, among other things, requires equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income; simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; eliminates the requirement for public business entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; requires an entity to present separately in other comprehensive income, the portion of the change in fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements; and clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities.

For the Company, the guidance in this ASU is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The adoption of this guidance in 2018 did not have a material impact on the Company’s consolidated financial statements.