Income Taxes (Provision for Income Taxes from Continuing Operations Differs from the Federal Statutory Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Statutory rate	$ 22,629	$ 16,397	$ 14,096
State taxes, less federal effect	3,650	3,194	2,901
Federal tax credits	(1,064)	(1,621)	(742)
Excess tax benefit on stock based compensation	(1,674)	(871)	(2,224)
Uncertain tax positions	0	(260)	(3,051)
Executive compensation	1,114	1,132	1,369
Change in valuation allowance	(130)	88	(1,694)
Net operating loss (NOL) write down	0	0	1,640
Change in Indemnification Asset	0	0	643
Other	(57)	94	73
Provision for income taxes	$ 24,468	$ 18,153	$ 13,011
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory rate	21.00%	21.00%	21.00%
State taxes, less federal effect	3.40%	4.10%	4.30%
Federal tax credits	(1.00%)	(2.10%)	(1.10%)
Excess tax benefit on stock based compensation	(1.60%)	(1.10%)	(3.30%)
Uncertain tax positions	0.00%	(0.30%)	(4.50%)
Executive compensation	1.00%	1.40%	2.00%
Change in valuation allowance	(0.10%)	0.10%	(2.50%)
Net operating loss (NOL) write down	0.00%	0.00%	2.40%
Change in Indemnification Asset	0.00%	0.00%	1.00%
Other	0.00%	0.10%	0.10%
Effective income tax rate, percentage	22.70%	23.20%	19.40%

Effective Income Tax Rate Reconciliation, Change In Indemnification Asset, Amount

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Effective Income Tax Rate Reconciliation, Net Operating Loss Write Down, Percent

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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