Vehicle Service Agreement Components of deferred services fees and accrued expenses and other liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Oct. 12, 2017	Dec. 31, 2016
Product Warranty Liability [Line Items]
Deferred service fees	$ 47,130	$ 41,113
Accrued expenses and other liabilities	14,786	10,359	$ 2,368
Extended Product Warranty Accrual	43,734	40,794		$ 38,713
Vehicle service agreement fees [Member]
Product Warranty Liability [Line Items]
Deferred service fees	43,495	40,531
Accrued expenses and other liabilities	239	263
Extended Product Warranty Accrual	$ 43,734	$ 40,794