Segments (Schedule of net sales, adjusted EBITDA and certain other measures by reportable segment) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net sales	$ 890,564	$ 964,249	$ 946,375	$ 825,405	$ 859,521	$ 990,264	$ 998,461	$ 834,202	$ 3,626,593	$ 3,682,448	$ 3,365,968
Gross profit	234,638	$ 254,767	$ 245,777	$ 216,122	229,230	$ 241,303	$ 239,599	$ 199,084	951,304	909,216	795,515
Depreciation & amortization									72,153	65,388	69,217
Total assets	1,906,101				1,576,111				1,906,101	1,576,111	1,473,350
Operating segments [Member] | Geographic divisions [Member]
Segment Reporting Information [Line Items]
Net sales									3,626,593	3,682,448	3,365,968
Gross profit									951,304	909,216	795,515
Depreciation & amortization									69,821	63,381	66,809
Adjusted EBITDA									335,878	340,464	250,061
Total assets	1,704,513				1,405,940				1,704,513	1,405,940	1,435,970
Other reconciling items [Member] | Other reconciling items [Member]
Segment Reporting Information [Line Items]
Net sales									0	0	0
Gross profit									0	0	0
Depreciation & amortization									2,332	2,007	2,408
Adjusted EBITDA									(76,445)	(74,585)	(50,058)
Total assets	$ 201,588				$ 170,171				$ 201,588	$ 170,171	$ 37,380