CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
NET SALES	$ 2,337,082	$ 2,263,061	$ 1,635,653
Cost of goods sold	1,914,211	1,847,195	1,356,738
GROSS PROFIT	422,871	415,866	278,915
Operating Expenses:
Warehouse and delivery	98,055	74,996	46,905
Selling, general and administrative	134,466	128,242	90,736
Amortization of intangible assets	35,908	34,213	19,374
Total operating expenses	268,429	237,451	157,015
OPERATING INCOME	154,442	178,415	121,900
Interest expense, net	36,616	26,436	8,790
Income before income taxes	117,826	151,979	113,110
Income taxes	28,260	32,147	27,392
NET INCOME	$ 89,566	$ 119,832	$ 85,718
BASIC NET INCOME PER COMMON SHARE (in USD per share)	$ 3.88	$ 4.99	$ 3.54
DILUTED NET INCOME PER COMMON SHARE (in USD per share)	$ 3.85	$ 4.93	$ 3.48
Weighted average shares outstanding - Basic (in shares)	23,058	23,995	24,230
Weighted average shares outstanding - Diluted (in shares)	23,280	24,317	24,643