SUPPLEMENTARY INFORMATION Schedule of Pass Through Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Other Operating Expenses [Line Items]
Cost of operations	$ 390,000	$ 351,000	$ 788,000	$ 722,000
Pass through costs [Member]
Other Operating Expenses [Line Items]
Cost of operations	$ 12,000	$ 10,000	$ 23,000	$ 23,000