Employee Benefit Plans (Narrative) (Details) - USD ($)	3 Months Ended			12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2007	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Stock-based compensation expense				$ 113,000	$ 82,000
Weighted average exercise price				$ 17.78	$ 17.76		$ 17.91
Employer's matching contribution			$ 1,350,000	$ 212,000	$ 199,000
Cash received from option exercises				$ 364,000	90,000
Debt and equity instruments included in the plan assets					12,132,000
Employer's safe harbor contribution rate				3.00%
Employer's safe harbor contribution payable				$ 250,000
Prior year contribution payable credited in current year					238,000
Defined contribution plan, cost recognized				248,000	$ 234,000
Percentage Of Increase Decrease In Pension Liability					9.00%
Settlement loss					$ 210,000
Excess funds transferred to 401(k) plan				$ 431,000
Treasury stock issued for stock plans, shares				1,880
Shares issued during period under employee stock purchase plans					2,134
Deferred compensation liability				$ 1,603,000	$ 1,602,000
Deferred compensation, compensation expense				42,000	40,000
Salary continuation liability				1,209,000	1,256,000
Salary continuation period expense				57,000	103,000
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Present value of future plan liability				166,000	215,000
Supplemental retirement plans, cost recognized during period				$ 16,000	$ 20,000
Employee Stock Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Stock options awarded				0
Award expiration period				10 years
Award expiration date				Feb. 17, 2025
Shares authorized under share-based payment awards				300,000
Shares available for grant				158,455
Exercise price, lower range limit				$ 17.65
Exercise price, upper range limit				18.00
Weighted average exercise price				$ 17.78
Weighted average remaining contractual life				3 years 9 months 15 days
Restricted Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of shares issued under long-term stock incentive plan				7,500	5,220
Award vesting period				3 years
Unrecognized compensation cost related to non-vested awards				$ 133,000
Employee Stock Purchase Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Shares authorized under share-based payment awards				250,000
Shares available for grant				171,079
Number of share per year in addition to prior unissued shares				5,000
JVB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Debt and equity instruments included in the plan assets					$ 12,182,000		$ 13,117,000
Defined benefit plan, pre-tax settlement charge	$ 943,000	$ 278,000
Excess funds transferred to 401(k) plan				$ (431,000)
Percentage of vested benefit						100.00%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Compensation costs not yet recognized				$ 1,000
Option price as a percentage of fair value				100.00%
Maximum [Member] | Employee Stock Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Award vesting period				5 years
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Option price as a percentage of fair value				95.00%
Minimum [Member] | Employee Stock Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Award vesting period				3 years