Revenue From Contracts with Customers - Schedule of Deferred Revenue Liabilities From Contracts with Customers (Rollforward) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Rollforward
Deferred Revenue, Beginning Balance	$ 75,754
Deferred Revenue, Ending Balance	86,692
Customer Contracts
Rollforward
Deferred Revenue, Beginning Balance	55,963
Deferred Revenue, Additions	55,474
Deferred Revenue, Revenue Recognized	47,042
Deferred Revenue, Ending Balance	64,395
Customer Contracts | Warranty coverage revenue
Rollforward
Deferred Revenue, Beginning Balance	39,835
Deferred Revenue, Additions	28,601
Deferred Revenue, Revenue Recognized	20,367
Deferred Revenue, Ending Balance	48,069
Customer Contracts | Car club revenue
Rollforward
Deferred Revenue, Beginning Balance	16,128
Deferred Revenue, Additions	26,873
Deferred Revenue, Revenue Recognized	26,675
Deferred Revenue, Ending Balance	$ 16,326