SUPPLEMENTARY INFORMATION Schedule of Pass Through Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Other Operating Expenses [Line Items]
Cost of operations	$ 398,000	$ 371,000
Pass through costs [Member]
Other Operating Expenses [Line Items]
Cost of operations	$ 11,000	$ 13,000