Share-Based Compensation (Narrative) (Details)		3 Months Ended		6 Months Ended
	May 13, 2021 USD ($) $ / shares shares	Jun. 30, 2022 USD ($) qtr plan shares	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) qtr plan $ / shares shares	Jun. 30, 2021 USD ($) shares	Dec. 31, 2021 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation plans | plan		3		3
Common stock reserved for issuance pursuant to outstanding awards		337,450		337,450		351,825
Weighted average grant date fair value (in dollars per share) | $ / shares				$ 42.03
Number of shares vested				4,000
Aggregate fair value of outstanding restricted shares and restricted stock units | $		$ 2,200,000		$ 2,200,000
Aggregate fair value of restricted shares and restricted stock units | $				159,000	$ 115,000
Proceeds from exercise of stock options | $				$ 239,000	$ 67,000
Number of shares vested				0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants, Forfeitures and Expirations in Period				0
Shares, Granted (in shares)				8,000
Unvested shares		61,901		61,901		57,901
Equity based compensation expense | $		$ 373,000	$ 337,000	$ 726,000	$ 671,000
Unrecognized compensation cost related to non-vested equity based compensation | $		$ 2,500,000		$ 2,500,000
Unrecognized equity based compensation weighted average period, years				2 years 5 months 8 days
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance (in shares)		387,507		387,507
Common stock reserved for issuance pursuant to outstanding awards		383,351		383,351
Vesting period, years				4 years
Expiration of stock options from date of grant				7 years
Weighted average remaining contractual term, years				2 years 11 months 4 days
Aggregate intrinsic value for all options outstanding | $		$ 5,900,000		$ 5,900,000
Weighted average remaining contractual term for exercisable options, years				2 years 25 days
Aggregate intrinsic value of exercisable options | $		4,900,000		$ 4,900,000
Aggregate intrinsic value of stock options exercised | $				314,000	87,000
Proceeds from exercise of stock options | $				239,000	67,000
Equity based compensation expense | $		126,000	125,000	249,000	248,000
Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity based compensation expense | $			57,000	$ 127,000	113,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years				4 years
Restricted stock units to common stock ratio, shares entitled, shares				1
Equity based compensation expense | $		$ 141,000	124,000	$ 282,000	247,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance (in shares)		129,411		129,411
Maximum contribution per plan year | $				$ 6,500
Number of shares purchased under the plan				0
Equity based compensation expense | $		$ 34,000	$ 31,000	$ 68,000	$ 63,000
Employees can purchase stock at the percentage rate of the lower of the market price on the first or last day of the offering period (as a percent)				85.00%
Employee Stock Purchase Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payroll deduction for employee stock purchase plan percentage				1.00%
Employee Stock Purchase Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payroll deduction for employee stock purchase plan percentage				10.00%
Non Employee Director Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance (in shares)		28,000		28,000
Common stock reserved for issuance pursuant to outstanding awards		8,000		8,000
Number of shares granted for non-employee directors upon re-election, shares				2,000
Number of quarterly installments in which awards will vest | qtr		4		4
Stock issued during period, shares	8,000
Stock granted, value | $	$ 336,000
Weighted average grant date fair value (in dollars per share) | $ / shares	$ 42.03
Number of shares vested				0
Unvested shares		8,000		8,000
Aggregate fair value of the unvested shares based on the closing price of entity's common stock | $		$ 280,000		$ 280,000
Equity based compensation expense | $		$ 72,000
Non Employee Director Stock Plan | Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Granted (in shares)				8,000