General - Concentration of Business (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Significant customers
Net revenue	$ 1,100,075	$ 1,154,289	$ 2,222,454	$ 2,273,295
Accounts receivable, net	753,065		$ 753,065		$ 680,569
Minimum
Significant customers
Term of contracts with customers			1 year
Term of contract extensions or renewals			1 year
Notice period for termination of contract			30 days
Maximum
Significant customers
Term of contracts with customers			3 years
Term of contract extensions or renewals			2 years
Notice period for termination of contract			180 days
Pennsylvania Counties
Significant customers
Net revenue			$ 272,200	271,400
CMS
Significant customers
Net revenue			112,300	133,200
Accounts receivable, net	$ 114,300		114,300		$ 117,400
United States federal government
Significant customers
Net revenue			$ 136,100	$ 156,700