Basis of presentation (Policies)	3 Months Ended
Mar. 31, 2021
Accounting Policies [Abstract]
Overview and presentation	The unaudited consolidated financial statements, including the notes thereto, have been prepared in accordance with United States generally accepted accounting principles (“GAAP”) interim reporting requirements and general banking industry guidelines, and therefore, do not include all information and notes included in the annual consolidated financial statements in conformity with GAAP. These interim consolidated financial statements and notes thereto should be read in conjunction with the Company’s audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K. The unaudited consolidated financial statements include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the results for the interim periods. The results for interim periods are not necessarily indicative of results for a full year. In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and the reported results of operations for the periods then ended. Actual results could differ significantly from those estimates.
Reclassifications	Certain prior period amounts have been reclassified to conform to the current period presentation without any impact on the reported amounts of net income or shareholders’ equity.
Earnings per share	Earnings per share Basic earnings per common share ("EPS") excludes dilution and is computed by dividing earnings available to common shareholders by the weighted average number of common shares outstanding during the period. Diluted EPS includes the dilutive effect of additional potential common shares issuable under the restricted stock units granted but not yet vested and distributable. Diluted EPS is computed by dividing earnings available to common shareholders by the weighted average number of common shares outstanding for the period, plus an incremental number of common-equivalent shares computed using the treasury stock method. Unvested share-based payment awards, which include the right to receive non-forfeitable dividends or dividend equivalents, are considered to participate with common shareholders in undistributed earnings for purposes of computing EPS. Companies that have such participating securities are required to calculate basic and diluted EPS using the two-class method. Certain restricted stock awards granted by the Company include non-forfeitable dividend equivalents and are considered participating securities. Calculations of EPS under the two-class method (i) exclude from the numerator any dividends paid or owed on participating securities and any undistributed earnings considered to be attributable to participating securities and (ii) exclude from the denominator the dilutive impact of the participating securities.
Recently adopted accounting policies, Recently adopted accounting standards and Newly issued not yet effective accounting standards	Recently adopted accounting policies: The Company did not modify or adopt any new accounting policies during the three months ended March 31, 2021 that were not disclosed in the Company's 2020 audited consolidated financial statements included on the Form 10-K, other than as described below. During the three months ended March 31, 2021, the Company reevaluated its business segments to align all retail mortgage activities with the Mortgage segment. Previously, the Company assigned retail mortgage activities within the Banking geographical footprint to the Banking segment. See Note 12, "Segment reporting" for additional information on this change. Recently adopted accounting standards: Except as set forth below, the Company did not adopt any new accounting standards that were not disclosed in the Company's 2020 audited consolidated financial statements included on Form 10-K. In January 2021, Financial Accounting Standards Board ("FASB") issued ASU 2021-01, "Reference Rate Reform (Topic 848): Scope". This ASU clarifies that certain optional expedients and exceptions in Topic 848 for contract modifications and hedge accounting apply to derivatives that are affected by the discounting transition. The ASU also amends the expedients and exceptions in Topic 848 to capture the incremental consequences of the scope clarification and to tailor the existing guidance to derivative instruments affected by the discounting transition. The Company early adopted ASU 2021-01 upon issuance effective January 7, 2021. No contract modifications have been made under the new guidance, therefore the adoption of this update did not impact the Company's financial statements or disclosures. Newly issued not yet effective accounting standards: The Company has reviewed newly issued not yet effective accounting standards and concluded as of March 31, 2021, there are none that are likely to impact the Company's financial statements or disclosures.

Basis of presentation (Policies)

3 Months Ended

Mar. 31, 2021

The unaudited consolidated financial statements, including the notes thereto, have been prepared in accordance with United States generally accepted accounting principles (“GAAP”) interim reporting requirements and general banking industry guidelines, and therefore, do not include all information and notes included in the annual consolidated financial statements in conformity with GAAP. These interim consolidated financial statements and notes thereto should be read in conjunction with the Company’s audited consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K.

The unaudited consolidated financial statements include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of the results for the interim periods. The results for interim periods are not necessarily indicative of results for a full year.

In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and the reported results of operations for the periods then ended. Actual results could differ significantly from those estimates.

Reclassifications

Certain prior period amounts have been reclassified to conform to the current period presentation without any impact on the reported amounts of net income or shareholders’ equity.

Earnings per share

Basic earnings per common share ("EPS") excludes dilution and is computed by dividing earnings available to common shareholders by the weighted average number of common shares outstanding during the period. Diluted EPS includes the dilutive effect of additional potential common shares issuable under the restricted stock units granted but not yet vested and distributable. Diluted EPS is computed by dividing earnings available to common shareholders by the weighted average number of common shares outstanding for the period, plus an incremental number of common-equivalent shares computed using the treasury stock method.

Unvested share-based payment awards, which include the right to receive non-forfeitable dividends or dividend equivalents, are considered to participate with common shareholders in undistributed earnings for purposes of computing EPS. Companies that have such participating securities are required to calculate basic and diluted EPS using the two-class method. Certain restricted stock awards granted by the Company include non-forfeitable dividend equivalents and are considered participating securities. Calculations of EPS under the two-class method (i) exclude from the numerator

any dividends paid or owed on participating securities and any undistributed earnings considered to be attributable to participating securities and (ii) exclude from the denominator the dilutive impact of the participating securities.

Recently adopted accounting policies, Recently adopted accounting standards and Newly issued not yet effective accounting standards

Recently adopted accounting policies:

The Company did not modify or adopt any new accounting policies during the three months ended March 31, 2021 that were not disclosed in the Company's 2020 audited consolidated financial statements included on the Form 10-K, other than as described below.

During the three months ended March 31, 2021, the Company reevaluated its business segments to align all retail mortgage activities with the Mortgage segment. Previously, the Company assigned retail mortgage activities within the Banking geographical footprint to the Banking segment. See Note 12, "Segment reporting" for additional information on this change.

Recently adopted accounting standards:

Except as set forth below, the Company did not adopt any new accounting standards that were not disclosed in the Company's 2020 audited consolidated financial statements included on Form 10-K.

In January 2021, Financial Accounting Standards Board ("FASB") issued ASU 2021-01, "Reference Rate Reform (Topic 848): Scope". This ASU clarifies that certain optional expedients and exceptions in Topic 848 for contract modifications and hedge accounting apply to derivatives that are affected by the discounting transition. The ASU also amends the expedients and exceptions in Topic 848 to capture the incremental consequences of the scope clarification and to tailor the existing guidance to derivative instruments affected by the discounting transition. The Company early adopted ASU 2021-01 upon issuance effective January 7, 2021. No contract modifications have been made under the new guidance, therefore the adoption of this update did not impact the Company's financial statements or disclosures.

Newly issued not yet effective accounting standards:

The Company has reviewed newly issued not yet effective accounting standards and concluded as of March 31, 2021, there are none that are likely to impact the Company's financial statements or disclosures.