REVENUES (Freight & Delivery Revenues) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues		$ 1,175,119	$ 1,309,890	$ 1,322,575	$ 1,049,242	$ 1,186,152	$ 1,418,758	$ 1,327,682	$ 996,511	$ 4,856,826	[1]	$ 4,929,103	[1]	$ 4,382,869	[1]
Freight & Delivery Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenues	[2]									(738,482)		(747,862)		(641,815)
Total Revenues Excluding Freight & Delivery [Member]
Disaggregation of Revenue [Line Items]
Total revenues										$ 4,118,344		$ 4,181,241		$ 3,741,054

[1] ¹ The geographic markets are defined by states as follows: East market — Arkansas, Delaware, Illinois, Kentucky, Maryland, North Carolina, Pennsylvania, Tennessee, Virginia, and Washington D.C. Gulf Coast market — Alabama, Florida, Georgia, Louisiana, Mexico, Mississippi, Oklahoma, South Carolina and Texas West market — Arizona, California and New Mexico

[2] Includes freight & delivery to remote distribution sites.