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Stock-Based Compensation - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exerciseable (in shares)	100,824	89,561	119,898
Options exerciseable, weighted average exercise price (in USD per share)	$ 26.50	$ 24.48	$ 21.55
Total intrinsic value of stock options outstanding and exercisable	$ 646,000	$ 670,000	$ 1,170,000
Stock-based compensation expense	$ 816,000	665,000	778,000
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
Total intrinsic value of stock options exercised	$ 383,000	631,000	208,000
Amount withheld for stock option exercises and related income taxes	227,000	1,100,000	1,100,000
Stock-based compensation expense	183,000	152,000	207,000
Unrecognized compensation expense	$ 298,000
Weighted-average period for recognition of expense	2 years 4 months 15 days
Cash Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from exercise of stock options	$ 195,000	69,000	0
Cashless Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from exercise of stock options	$ 193,000	954,000	847,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan vesting period, years	3 years
Total intrinsic value of stock options exercised	$ 654,000	676,000	501,000
Stock-based compensation expense	633,000	$ 513,000	$ 571,000
Unrecognized compensation expense	$ 1,700,000
Weighted-average period for recognition of expense	2 years 3 months 1 day
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
2017 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of authorized stock for stock incentive plan (in shares)	350,000

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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