CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Sales	$ 1,904,523	$ 2,089,888	$ 3,535,823	$ 3,790,324
Cost of sales	1,387,367	1,593,560	2,576,692	2,882,944
Gross margin	517,156	496,328	959,131	907,380
Selling, general and administrative expenses	401,511	391,769	771,595	750,677
Income from operations	115,645	104,559	187,536	156,703
Interest expense, net	29,382	28,957	54,283	55,699
Income before income taxes	86,263	75,602	133,253	101,004
Income tax expense	19,659	18,980	30,941	21,162
Net income	66,604	56,622	102,312	79,842
Comprehensive income	$ 66,604	$ 56,622	$ 102,312	$ 79,842
Net income per share:
Basic	$ 0.58	$ 0.49	$ 0.89	$ 0.70
Diluted	$ 0.57	$ 0.49	$ 0.88	$ 0.68
Weighted average common shares:
Basic	115,757	114,636	115,592	114,365
Diluted	116,919	116,693	116,726	116,695