Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue	$ 389,050	$ 393,222	$ 662,305	$ 696,651
Service Revenue [Member]
Revenue	234,139	234,606	417,262	406,978
Commission Revenue [Member]
Revenue	125,465	134,466	218,950	226,746
Fees Revenue [Member]
Revenue	108,674	100,140	198,312	180,232
Inventory Sales Revenue [Member]
Revenue	$ 154,911	$ 158,616	$ 245,043	$ 289,673