Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance For Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 1,048	$ 1,088	$ 828
Increase	1,526	658	320
Decrease	1,055	698	60
Balance at end of year	1,519	1,048	1,088
Tax Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	6,720	6,870	10,593
Increase	27,226
Decrease		150	3,723
Balance at end of year	$ 33,946	$ 6,720	$ 6,870