Operating expenses (Schedule of Direct Operating Expenses) (Details) - Service Revenues [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Ancillary and logistical service expenses	$ 10,755	$ 12,269
Employee compensation expenses	15,921	14,530
Buildings, facilities and technology expenses	3,854	2,701
Travel, advertising and promotion expenses	5,172	4,518
Other costs of services	3,313	3,848
Total direct expenses	$ 39,015	$ 37,866