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Share-Based Compensation (Narrative) (Details) $ / shares in Units, $ in Thousands |  |  | 12 Months Ended
--- | --- | --- | ---
May 22, 2019 | Feb. 26, 2019 | Dec. 31, 2020 USD ($) Director $ / shares shares | Dec. 31, 2019 Director $ / shares shares | Dec. 31, 2018 USD ($) Director $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Expiration period |  |  | 10 years |  |
Stock options awarded |  |  | 0 | 0 | 0
Unrecognized compensation expense | $ |  |  | $ 0 |  |
Aggregate intrinsic value | $ |  |  |  |  | $ 236
Proceeds from stock options exercised | $ |  |  |  |  | $ 320
Director [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Grant date fair value | $ / shares |  |  | $ 19.54 | $ 29.78 | $ 29.03
Shares issued in lieu of cash |  |  | 8,439 | 4,192 | 6,363
Number of non-employee directors | Director |  |  | 4 | 3 | 5
Restricted Stock Awards [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Unrecognized compensation expense | $ |  |  | $ 2,000 |  |
Expected recognition expense period, weighted average period in years |  |  | 1 year 9 months 18 days |  |
TSR Performance Requirement [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Expected term | 2 years 7 months 9 days | 2 years 10 months 2 days |  |  | 2 years 10 months 2 days
Risk free interest rate | 2.18% | 2.43% |  |  | 2.39%
Expected dividend yield | 3.60% | 3.20% |  |  | 2.83%
Expected stock price volatility | 22.00% | 21.30% |  |  | 21.20%
2015 Long-Term Incentive Plan [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Number of shares available for grant |  |  | 156,000 |  |
Non-employee Directors Stock Incentive Plan [Member] | Restricted Stock Awards [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Required service period |  |  | 1 year | 1 year | 1 year
Restricted shares of common stock awarded |  |  | 12,798 | 8,226 | 7,370
Grant date fair value | $ / shares |  |  | $ 17.57 | $ 27.33 | $ 33.90
Non-employee Directors Stock Incentive Plan [Member] | Restricted Stock Awards [Member] | Vested Immediately [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share based compensation, vesting percentage |  |  | 50.00% |  |
Restricted shares of common stock awarded |  |  | 6,399 | 4,113 | 3,690
Non-employee Directors Stock Incentive Plan [Member] | Restricted Stock Awards [Member] | Vested After Completion of One-Year Service Requirement [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share based compensation, vesting percentage |  |  | 50.00% |  |
Restricted shares of common stock awarded |  |  | 6,399 | 4,113 | 3,680
Management Stock Incentive Plan [Member] | Restricted Stock Awards [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Required service period |  |  | 3 years | 3 years | 3 years
Grant date fair value | $ / shares |  |  | $ 25.02 | $ 25.60 | $ 27.76
Share-based vesting date |  |  |  | Feb. 26, 2022 | Feb. 27, 2021
Management Stock Incentive Plan [Member] | Restricted Stock Awards [Member] | TSR Performance Requirement [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Required service period |  |  |  | 3 years | 1 year
Management Stock Incentive Plan [Member] | PSUs [Member] | ROAE Return on Average Equity [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share based compensation, vesting percentage |  |  | 50.00% |  |
Required service period |  |  | 3 years |  |
Share-based vesting description |  |  | The shares earned based on the achievement of the ROAE performance requirement, if any, will vest on the third anniversary of the grant date assuming the recipient’s continuous service to the Company. |  |
Management Stock Incentive Plan [Member] | PSUs [Member] | ROAA Performance Requirement [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share based compensation, vesting percentage |  |  | 50.00% | 50.00% |
Required service period |  |  | 3 years |  |
Share-based vesting description |  |  | The shares earned based on the achievement of the ROAA performance requirement, if any, will vest on the third anniversary of the grant date assuming the recipient’s continuous service to the Company. If earned at target level, members of management will receive up to 23,302 shares of our common stock in the aggregate. |  |
Management Stock Incentive Plan [Member] | PSUs [Member] | TSR Performance Requirement [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Share based compensation, vesting percentage |  |  |  | 50.00% |
Maximum [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period |  |  | 5 years |  |
Maximum [Member] | Restricted Stock Awards [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period |  |  | 3 years |  |
Maximum [Member] | 2015 Long-Term Incentive Plan [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Maximum number of grants authorized |  |  | 438,076 |  |
Maximum [Member] | Management Stock Incentive Plan [Member] | Restricted Stock Awards [Member] | ROAA Performance Requirement [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Restricted shares of common stock awarded |  |  | 23,302 |  |
Maximum [Member] | Management Stock Incentive Plan [Member] | Restricted Stock Awards [Member] | Vested After Completion of Three-Year Service Requirement [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Restricted shares of common stock awarded |  |  | 58,806 | 54,476 | 37,676
Maximum [Member] | Management Stock Incentive Plan [Member] | Restricted Stock Awards [Member] | TSR Performance Requirement [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Restricted shares of common stock awarded |  |  |  | 21,970 | 14,877
Minimum [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period |  |  | 3 years |  |
Minimum [Member] | Restricted Stock Awards [Member] |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Award vesting period |  |  | 2 years |  |

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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iii) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iv) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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