Property and Equipment - Components of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Total, at cost	$ 1,634,978	$ 1,464,795
Less accumulated depreciation	(510,678)	(450,184)
Subtotal	1,124,300	1,014,611
Less assets held for sale	(3,489)	(4,231)
Property and equipment, net	1,120,811	1,010,380
Land [Member]
Property Plant And Equipment [Line Items]
Total, at cost	351,367	306,457
Building and Improvements [Member]
Property Plant And Equipment [Line Items]
Total, at cost	869,382	777,766
Software and Computer Equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	143,239	128,366
Parts and Service Equipment [Member]
Property Plant And Equipment [Line Items]
Total, at cost	104,483	93,901
Office Equipment and Fixtures [Member]
Property Plant And Equipment [Line Items]
Total, at cost	95,236	86,216
Company Vehicles [Member]
Property Plant And Equipment [Line Items]
Total, at cost	9,595	9,107
Construction in Progress [Member]
Property Plant And Equipment [Line Items]
Total, at cost	$ 61,676	$ 62,982