Stock Incentive Plan - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of authorized stock for stock incentive plan (in shares)	350,000		350,000
Stock-based compensation expense			$ 544	$ 571
Shares issued upon exercise of stock options (in shares)	2,533	11,427	4,256	12,423
Proceeds from stock option exercises		$ 195		$ 195
Shares withheld for stock option exercises and related income taxes, amount withheld	$ 268	$ 154	$ 317	$ 227
Options granted (in shares)	0	0	0	0
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
Stock-based compensation expense	$ 32	$ 31	$ 97	$ 139
Cashless Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from stock option exercises	137	74	$ 203	130
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	$ 161	$ 128	$ 447	$ 432
Restricted stock units granted (in shares)	0	0	0	0

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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