Share-Based Compensation And Share Repurchase Plans (Narrative) (Details) - USD ($)							1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended			21 Months Ended
	Dec. 08, 2021	Aug. 11, 2021	Dec. 16, 2020	Dec. 16, 2020	Mar. 10, 2020	Mar. 05, 2020	Apr. 30, 2021	Jun. 30, 2021	Sep. 30, 2018	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021	Mar. 14, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized estimated compensation cost related to non-vested stock options granted										$ 248,000			$ 248,000
Recognition period of unrecognized compensation cost										1 year 1 month 20 days
Intrinsic unrealized value of all options outstanding, vested and expected to vest												$ 136,350,000
Number of Stock Options, Granted										0
Stock option expiry period										5 years
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense										$ 402,000	$ 460,000	458,000
Proceeds from stock option exercises										$ 0		$ 906,000
2020 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock authorized for issuance											1,250,000
Common Stock shares remaining for future issuances											735,738
Class A [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock authorized for issuance										1,505,598			1,505,598
Number of Stock Options, Granted											38,803	219,408
Class A [Member] | 2020 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock shares remaining for future issuances										183,692			183,692
Class B [Member] | 2020 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock authorized for issuance											200,000
2017 Stock Repurchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase program, amount authorized					$ 25,000,000.0
Repurchase program, remaining amount authorized										$ 26,000,000.0			$ 26,000,000.0
Stock buy-back program period										2 years
2017 Stock Repurchase Plan [Member] | Class A [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase program, remaining amount authorized					$ 26,000,000.0
$25 Million Stock Repurchase Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase program, amount authorized														$ 25,000,000.0
$25 Million Stock Repurchase Program [Member] | Class A Nonvoting Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase value										$ 24,000,000.0			$ 24,000,000.0
Share price										$ 13.39
Shares repurchased plan, shares										1,792,819
$25 Million Stock Repurchased At $8.92 [Member] | Class A Nonvoting Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price								$ 8.92
Shares repurchased plan, shares								75,157					0
$25 Million Stock Repurchased At $7.30 [Member] | Class A Nonvoting Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price						$ 7.30
Shares repurchased plan, shares						25,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense										$ 1,800,000	$ 1,000,000.0
Unrecognized estimated compensation cost related to non-vested stock options granted										$ 2,900,000			$ 2,900,000
Vesting period of stock options and RSU				1 year						4 years
Number of options, Granted				114,803	287,163		262,830			1,059,108
Restricted Stock Units (RSUs) [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				100.00%					100.00%	25.00%
Restricted Stock Units (RSUs) [Member] | Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage							50.00%
Non-employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Stock Options, Granted			38,803
Non-employee Director [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Granted	48,951	26,924	60,084
Non-employee Director [Member] | Restricted Stock Units (RSUs) [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			75.00%
Vesting period of stock options and RSU			4 years
Non-employee Director [Member] | Restricted Stock Units (RSUs) [Member] | Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			25.00%
Non-employee Director [Member] | Restricted Stock Units (RSUs) [Member] | Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			50.00%
Vesting period of stock options and RSU			4 years
Employees [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock options and RSU							4 years
Number of options, Granted							22,888
Employees [Member] | Restricted Stock Units (RSUs) [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage							25.00%