- Components of Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets by Major Class [Line Items]
Gross Carrying Amount	$ 522,354	$ 193,137
Accumulated Amortization	(94,136)	(76,634)	$ (49,130)
Net	428,218	116,503
Total other intangible assets, Gross Carrying Amount	964,653	423,846	$ 420,546
Total other intangible assets, net	$ 870,517	$ 347,212
Non-compete agreements
Intangible Assets by Major Class [Line Items]
Estimated Life (Years)	4 years	5 years
Gross Carrying Amount	$ 2,630	$ 540
Accumulated Amortization	(329)	(540)
Net	2,301	0
Dealer/customer related
Intangible Assets by Major Class [Line Items]
Gross Carrying Amount	506,401	169,694
Accumulated Amortization	(85,614)	(60,638)
Net	$ 420,787	$ 109,056
Dealer/customer related | Minimum
Intangible Assets by Major Class [Line Items]
Estimated Life (Years)	5 years	5 years
Dealer/customer related | Maximum
Intangible Assets by Major Class [Line Items]
Estimated Life (Years)	20 years	10 years
Developed technology
Intangible Assets by Major Class [Line Items]
Gross Carrying Amount	$ 13,323	$ 22,903
Accumulated Amortization	(8,193)	(15,456)
Net	$ 5,130	$ 7,447
Developed technology | Minimum
Intangible Assets by Major Class [Line Items]
Estimated Life (Years)	5 years	5 years
Developed technology | Maximum
Intangible Assets by Major Class [Line Items]
Estimated Life (Years)	7 years	7 years
Non-amortizable—brand/trade names
Intangible Assets by Major Class [Line Items]
Non-amortizable—brand/trade names	$ 442,299	$ 230,709
Non-amortizable, Net	$ 442,299	$ 230,709