Acquisitions (Detail) - USD ($) $ in Thousands		Oct. 10, 2017	Sep. 30, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill			$ 47,803	$ 49,464
Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		144 months
Above Market Leases [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		153 months
Gross Value [Member]
Business Acquisition [Line Items]
Accounts receivable			14,668
Other assets			734
Inventories			103,876
Property and equipment			24,179
Customer relationships			29,660
Above-market leases			567
Goodwill			48,609
Total assets acquired			222,293
Accounts payable and accrued expenses			3,210
Other current liabilities			10,114
Total liabilities assumed			13,324
Total purchase price			208,969
Adjustments [Member]
Business Acquisition [Line Items]
Inventories	[1]		1,661
Goodwill	[1]		(1,661)
Total assets acquired	[1]		0
Total liabilities assumed	[1]		0
Total purchase price	[1]		0
Net Value [Member]
Business Acquisition [Line Items]
Accounts receivable			14,668
Other assets			734
Inventories			105,537
Property and equipment			24,179
Customer relationships			29,660
Above-market leases			567
Goodwill			46,948
Total assets acquired			222,293
Accounts payable and accrued expenses			3,210
Other current liabilities			10,114
Total liabilities assumed			13,324
Total purchase price			$ 208,969

[1] The Company obtained further information regarding the fair value of acquired inventory based on information that existed as of the acquisition date.