Segment Reporting (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Operations of the Company's operating segments
Net Sales to External Customers	$ 679,452,000	$ 660,821,000
Revenue Transactions With Other Operating Segments	0	0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Net Sales	679,452,000	660,821,000
Segment Profit	147,841,000	139,546,000
Goodwill	535,517,000	544,784,000	$ 534,780,000
Us Operations segment Member
Operations of the Company's operating segments
Net Sales to External Customers	234,650,000	229,745,000
Revenue Transactions With Other Operating Segments	26,145,000	23,666,000
Net Sales	260,795,000	253,411,000
Segment profit	37,985,000	34,245,000
Goodwill	410,021,000	409,471,000
Swiss Operations segment Member
Operations of the Company's operating segments
Net Sales to External Customers	33,577,000	32,466,000
Revenue Transactions With Other Operating Segments	153,731,000	143,582,000
Net Sales	187,308,000	176,048,000
Segment profit	53,522,000	45,975,000
Goodwill	21,757,000	22,866,000
Western European Operations [Member]
Operations of the Company's operating segments
Net Sales to External Customers	165,906,000	165,372,000
Revenue Transactions With Other Operating Segments	44,045,000	41,012,000
Net Sales	209,951,000	206,384,000
Segment profit	25,725,000	18,282,000
Goodwill	88,208,000	95,938,000
Chinese Operations [Member]
Operations of the Company's operating segments
Net Sales to External Customers	121,723,000	113,930,000
Revenue Transactions With Other Operating Segments	56,857,000	60,407,000
Net Sales	178,580,000	174,337,000
Segment profit	59,484,000	59,553,000
Goodwill	663,000	722,000
Other Operations [Member]
Operations of the Company's operating segments
Net Sales to External Customers	123,596,000	119,308,000
Revenue Transactions With Other Operating Segments	1,261,000	1,640,000
Net Sales	124,857,000	120,948,000
Segment profit	13,187,000	13,881,000
Goodwill	14,868,000	15,787,000
Intersegment Elimination [Member]
Operations of the Company's operating segments
Net Sales to External Customers	0	0
Revenue Transactions With Other Operating Segments	(282,039,000)	(270,307,000)
Net Sales	(282,039,000)	(270,307,000)
Segment profit	(42,062,000)	(32,390,000)
Goodwill	$ 0	$ 0