Pension and Other Retirement Plans (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) employee	Sep. 30, 2019 USD ($)
Defined Contribution Plans
Expense recognized	$ 167,000	$ 178,000	$ 570,000	$ 503,000
401(K) Plan [Member]
Defined Contribution Plans
Maximum pretax contribution per employee			100.00%
Defined contribution plan, employer matching contribution, percent			1.50%
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of employee participants | employee			1,400
Defined Benefit Plan, Estimated Future Employer Contributions
Estimated future employer contributions	$ 0		$ 0