Summary of Significant Accounting Policies - Schedule of Activity Related to Resale Value Guarantee Program (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Lease Vehicles
Operating lease vehicles—beginning of period	$ 849,800
Net increase in operating lease vehicles	(1,573,860)	$ (1,050,264)	$ (460,561)
Depreciation expense recorded in cost of automotive revenues	(130,355)	(63,105)
Additional depreciation expense recorded in cost of automotive revenues as a result of early cancellation of resale value guarantee	(21,487)	(9,251)
Operating lease vehicles—end of period	2,000,000	849,800
Resale Value Guarantee
Net increase in resale value guarantee	(442,295)	(249,492)	(236,299)
Resale Value Guarantee [Member]
Operating Lease Vehicles
Operating lease vehicles—beginning of period	684,590	376,979
Net increase in operating lease vehicles	1,047,220	380,627
Increases to inventory from vehicles returned under our trade- in program	(23,439)	(660)
Operating lease vehicles—end of period	1,556,529	684,590	376,979
Deferred Revenue
Deferred revenue—beginning of period	381,096	230,856
Net increase in deferred revenue from new vehicle deliveries and reclassification of collateralized borrowing from long-term to short-term	553,765	280,542
Amortization of deferred revenue and short-term collateralized borrowing recorded in automotive revenue	(229,624)	(118,570)
Additional revenue recorded in automotive revenue as a result of early cancellation of resale value guarantee	(12,352)	(9,590)
Recognition of deferred revenue resulting from return of vehicle under trade-in program	(13,753)	(2,142)
Deferred revenue—end of period	679,132	381,096	230,856
Resale Value Guarantee
Resale value guarantee liability—beginning of period	487,880	236,298
Net increase in resale value guarantee	1,013,733	262,526
Reclassification from long-term to short-term collateralized borrowing	(29,612)
Additional revenue recorded in automotive revenue as a result of early cancellation of resale value guarantee	(11,042)	(8,557)
Release of resale value guarantee resulting from return of vehicle under trade-in program	(30,386)	(2,387)
Resale value guarantee liability—end of period	$ 1,430,573	$ 487,880	$ 236,298