Stock-Based Compensation Restricted Stock Grants (Details) - Restricted stock - $ / shares	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards in the period	59,311	55,198
Weighted Average Grant Date Fair Value, Stock Awards	$ 28.22	$ 29.84
Non-Employee Director \| Two-year vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards in the period	8,295	8,368
Employee \| Four-year vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards in the period	26,015	22,403
Employee \| Performance-based vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards in the period	25,001	24,427

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).

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=116856206&loc=d3e5070-113901

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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).

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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