Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Sep. 30, 2019
Operations of the Company's operating segments
Net Sales to External Customers	$ 924,351	$ 690,673	$ 1,728,741	$ 1,339,835
Revenue Transactions With Other Operating Segments	0	0	0	0
Net Sales	924,351	690,673	1,728,741	1,339,835
Segment Profit	255,256	176,643	465,928	317,921
Goodwill	642,186		642,186		$ 550,270	$ 537,624
Swiss Operations [Member]
Operations of the Company's operating segments
Net Sales to External Customers	40,836	28,948	80,117	60,844
Revenue Transactions With Other Operating Segments	201,182	142,487	385,647	295,336
Net Sales	242,018	171,435	465,764	356,180
Segment profit	69,516	48,248	134,395	102,158
Goodwill	23,553		23,553			22,830
Western European Operations [Member]
Operations of the Company's operating segments
Net Sales to External Customers	201,722	149,051	394,072	302,376
Revenue Transactions With Other Operating Segments	55,873	39,699	108,128	81,413
Net Sales	257,595	188,750	502,200	383,789
Segment profit	38,476	30,345	76,342	54,452
Goodwill	93,133		93,133			84,975
Chinese Operations [Member]
Operations of the Company's operating segments
Net Sales to External Customers	205,521	140,907	361,595	241,506
Revenue Transactions With Other Operating Segments	72,529	45,731	141,607	94,480
Net Sales	278,050	186,638	503,202	335,986
Segment profit	94,663	63,955	166,687	109,505
Goodwill	697		697			621
Other Operations [Member]
Operations of the Company's operating segments
Net Sales to External Customers	152,962	122,427	297,688	244,359
Revenue Transactions With Other Operating Segments	1,275	875	2,371	1,771
Net Sales	154,237	123,302	300,059	246,130
Segment profit	21,414	13,122	41,586	24,148
Goodwill	15,203		15,203			14,828
Intersegment Elimination [Member]
Operations of the Company's operating segments
Net Sales to External Customers	0	0	0	0
Revenue Transactions With Other Operating Segments	(369,366)	(256,307)	(713,045)	(526,904)
Net Sales	(369,366)	(256,307)	(713,045)	(526,904)
Segment profit	(48,085)	(31,608)	(96,025)	(69,861)
Goodwill	0		0			0
US Operations [Member]
Operations of the Company's operating segments
Net Sales to External Customers	323,310	249,340	595,269	490,750
Revenue Transactions With Other Operating Segments	38,507	27,515	75,292	53,904
Net Sales	361,817	276,855	670,561	544,654
Segment profit	79,272	$ 52,581	142,943	$ 97,519
Goodwill	$ 509,600		$ 509,600			$ 414,370