Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance For Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 1,519	$ 1,048	$ 1,088
Increase	386	1,526	658
Decrease	523	1,055	698
Balance at end of year	1,382	1,519	1,048
Tax Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	33,946	6,720	6,870
Increase	13,110	27,226
Decrease			150
Balance at end of year	$ 47,056	$ 33,946	$ 6,720