Acquisitions (Details) $ in Millions	9 Months Ended
	Oct. 01, 2017 USD ($) store	Oct. 02, 2016 USD ($)	Sep. 30, 2017 location	Aug. 31, 2017 location	May 31, 2017 location	Mar. 31, 2017 location	Feb. 28, 2017 location	Jan. 31, 2017 location	Sep. 30, 2016 location	Apr. 30, 2016 location	Jan. 31, 2016 location
Business Acquisition [Line Items]
Cash consideration | $	$ 66.8	$ 58.5
Number of locations | store	475
Marshall Stone
Business Acquisition [Line Items]
Number of locations			2
South Coast Supply
Business Acquisition [Line Items]
Number of locations				2
Evergreen
Business Acquisition [Line Items]
Number of locations					2
Angelo's Supplies
Business Acquisition [Line Items]
Number of locations						2
Stone Forest
Business Acquisition [Line Items]
Number of locations							1
Aspen Valley
Business Acquisition [Line Items]
Number of locations								3
Glen Allen
Business Acquisition [Line Items]
Number of locations									1
Bissett
Business Acquisition [Line Items]
Number of locations				3
Blue Max
Business Acquisition [Line Items]
Number of locations										5
Hydro-Scape
Business Acquisition [Line Items]
Number of locations											17
Los Angeles area | AB Supply
Business Acquisition [Line Items]
Number of locations						10
Las Vegas | AB Supply
Business Acquisition [Line Items]
Number of locations						2