Income Taxes (Provision for Income Taxes from Continuing Operations Differs from the Federal Statutory Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Statutory rate	$ 17,800	$ 16,788	$ 27,268
State taxes, less federal effect	3,219	3,242	2,442
Federal tax credits	(1,967)	(3,680)	(373)
Excess tax benefit on stock based compensation	(961)	(2,288)	(1,415)
Uncertain tax positions	(260)	(3,051)	(148)
Executive compensation	1,132	1,369	160
Change in valuation allowance	88	844	660
Net operating loss (NOL) write down	0	1,640	0
Change in Indemnification Asset	0	643	0
Tax effect of Tax Reform Act	0	0	(12,535)
Domestic manufacturer's deduction	0	0	(1,578)
Other	621	629	462
Provision for income taxes	$ 19,672	$ 16,136	$ 14,943
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory rate	21.00%	21.00%	35.00%
State taxes, less federal effect	3.80%	4.10%	3.10%
Federal tax credits	(2.30%)	(4.60%)	(0.50%)
Excess tax benefit on stock based compensation	(1.10%)	(2.90%)	(1.80%)
Uncertain tax positions	(0.30%)	(3.80%)	(0.20%)
Executive compensation	1.30%	1.70%	0.20%
Change in valuation allowance	0.10%	1.10%	0.80%
Net operating loss (NOL) write down	0.00%	2.10%	0.00%
Change in Indemnification Asset	0.00%	0.80%	0.00%
Tax effect of Tax Reform Act	0	0	(0.161)
Domestic manufacturer's deduction	0.00%	0.00%	(2.00%)
Other	0.70%	0.70%	0.70%
Effective income tax rate, percentage	23.20%	20.20%	19.20%