Stock-Based Compensation - Narrative (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable (in shares)	136,038	112,319	100,824
Options exercisable, weighted average exercise price (in USD per share)	$ 29.42	$ 28.17	$ 26.50
Total intrinsic value of stock options outstanding	$ 682,000	$ 1,100,000	$ 646,000
Total intrinsic value of stock options exercisable	682,000	1,100,000	646,000
Total intrinsic value of stock options exercised	0	203,000	383,000
Stock-based compensation expense	$ 943,000	832,000	816,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation options contractual term	10 years
Stock incentive plan vesting period, years	3 years
Amount withheld for stock option exercises and related income taxes	$ 0	317,000	227,000
Stock-based compensation expense	148,000	143,000	183,000
Unrecognized compensation expense	$ 258,000
Weighted-average period for recognition of expense	2 years 2 months 12 days
Cash Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from exercise of stock options	$ 0	0	195,000
Cashless Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from exercise of stock options	$ 0	282,000	193,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan vesting period, years	3 years
Stock-based compensation expense	$ 795,000	689,000	633,000
Unrecognized compensation expense	$ 1,500,000
Weighted-average period for recognition of expense	2 years 2 months 12 days
Intrinsic value of restricted stock units vested	$ 735,000	$ 906,000	$ 654,000
Prior Stock Option Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of authorized stock for stock incentive plan (in shares)	0
2020 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of authorized stock for stock incentive plan (in shares)	325,000

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Number of shares authorized for issuance under share-based payment arrangement.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Intrinsic value of vested award under share-based payment arrangement. Excludes share and unit options.

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