Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue
Disaggregated sales	$ 3,091,595	$ 2,589,874	$ 5,568,082	$ 5,000,482
DIY customer [Member]
Disaggregation of Revenue
Disaggregated sales	1,853,115	1,434,146	3,198,597	2,771,175
Professional service provider customer [Member]
Disaggregation of Revenue
Disaggregated sales	1,175,030	1,113,485	2,245,229	2,152,266
Other sales and sales adjustments [Member]
Disaggregation of Revenue
Disaggregated sales	$ 63,450	$ 42,243	$ 124,256	$ 77,041