Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance For Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 1,088	$ 828	$ 426
Additions	658	320	1,010
Deductions	698	60	608
Balance at end of year	1,048	1,088	828
Tax Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	6,870	10,593	11,530
Additions
Deductions	150	3,723	937
Balance at end of year	$ 6,720	$ 6,870	$ 10,593