Vehicle Service Agreement Liability - Reconciliation of the changes in the vehicle service agreement liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Product Warranty Liability [Line Items]
Recognition of service fees on vehicle service agreements	$ (14,500)	$ (16,000)
Vehicle service agreement fees
Product Warranty Liability [Line Items]
Balance at January 1, net	43,734	40,794
Vehicle service agreement liability acquired during the year related to the purchase of Geminus	10,792	0
Gross service fees for vehicle service agreements sold	19,384	22,556
Recognition of service fees on vehicle service agreements	(24,865)	(18,939)
Liability for claims authorized on vehicle service agreements	9,141	5,711
Payments of claims authorized on vehicle service agreements	(6,095)	(5,735)
Re-estimation of deferred service fees	(368)	(653)
Balance at December 31, net	$ 51,723	$ 43,734