Financial Instruments (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2017
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Unrealized loss on derivative, net of tax	$ 264	$ 2,261	$ 4,358	$ 3,546
Amounts reclassified from accumulated other comprehensive loss, net of tax			672
Interest expense	2,351	$ 1,718	4,053	$ 3,327
Derivative instruments, net of tax [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Amounts reclassified from accumulated other comprehensive loss, net of tax			672
Interest Rate Swap [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Interest rate swap notional amount	$ 140,600		$ 140,600			$ 144,400	$ 155,300
Fixed interest rate	2.928%		2.928%			2.928%	1.4935%
Fair value of interest rate swap	$ 11,200		$ 11,200			$ 6,300
Unrealized loss on interest rate swap			4,900
Unrealized loss on derivative, net of tax			3,700
Gain On Contract Termination					$ 3,500
Amounts reclassified from accumulated other comprehensive loss			900
Amounts reclassified from accumulated other comprehensive loss, net of tax			$ 700