Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Examination [Line Items]
Deferred Tax Assets, Valuation Allowance		$ 0	$ 0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	21.00%	35.00%
Anticipated Reduction Resulting from Lapse of Applicable Statue of Limitations		$ 496,000	$ 503,000
Income tax interest and penalties		600,000	200,000	$ 200,000
Accrued income tax interest and penalties		700,000	500,000
Change in statutory tax rate		0	$ 0	$ 7,070,000
Increase in provisional amount, a component of income tax expense		$ 100,000
Forecast [Member]
Income Tax Examination [Line Items]
Anticipated Reduction Resulting from Lapse of Applicable Statue of Limitations	$ 600,000