Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Deferred Tax Assets Tax Deferred Compensation Noncurrent	$ 1,063,000								$ 1,063,000		$ 1,170,000
Income tax expense (benefit)	2,680,000	$ 1,130,000	$ (3,805,000)	$ 700,000	$ 1,560,000	$ 1,460,000	$ 1,850,000	$ 550,000	705,000	$ 5,420,000	5,700,000
Income Tax Examination, Penalties and Interest Accrued	0				0				0	0
Effective income tax rate reconciliation related to impairment losses, tax benefit									(1,400,000)
Effective income tax rate reconciliation related to executive compensation									1,000,000.0
Income Tax Examination, Penalties and Interest Expense									600	2,100	$ 31,000
Deferred tax asset, valuation allowance	0				0				0	0
Unrecognized tax benefits, income tax penalties accrued	$ 0				$ 0				$ 0	$ 0
Effective income tax rate reconciliation, percent									(58.40%)	29.00%