Segments (Schedule of net sales, adjusted EBITDA and certain other measures by reportable segment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net sales	$ 979,896	$ 946,375	$ 1,900,775	$ 1,771,780
Gross profit	252,822	245,777	489,950	461,899
Depreciation & amortization	20,299	17,632	40,294	34,424
Operating segments [Member] | Geographic divisions [Member]
Segment Reporting Information [Line Items]
Net sales	979,896	946,375	1,900,775	1,771,780
Gross profit	252,822	245,777	489,950	461,899
Depreciation & amortization	19,776	17,000	39,277	33,147
Adjusted EBITDA	106,466	90,017	186,842	163,785
Other reconciling items [Member] | Other reconciling items [Member]
Segment Reporting Information [Line Items]
Net sales	0	0	0	0
Gross profit	0	0	0	0
Depreciation & amortization	523	632	1,017	1,277
Adjusted EBITDA	$ (16,117)	$ (16,688)	$ (35,487)	$ (36,056)