Segment Reporting Segment Details (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
Revenues	$ 843,968	$ 753,866	$ 731,366	$ 679,452	$ 817,923	$ 734,846	$ 721,996	$ 660,821	$ 3,008,652	$ 2,935,586	$ 2,725,053
Revenue Transactions With Other Operating Segments									0	0	0
Net Sales									3,008,652	2,935,586	2,725,053
Total Segment Profit									778,078	730,505	652,582
Depreciation									38,991	37,167	33,458
Assets	2,789,321				2,618,847				2,789,321	2,618,847	2,549,805
Purchase of property, plant and equipment									(97,341)	(142,726)	(127,426)
Goodwill	535,979				534,780				535,979	534,780	539,838
U.S. Operations Segment
Revenues									1,057,115	1,007,798	944,825
Revenue Transactions With Other Operating Segments									114,794	104,458	99,117
Net Sales									1,171,909	1,112,256	1,043,942
Segment Profit									210,133	161,615	177,705
Depreciation									10,684	10,425	7,659
Assets	2,363,725				2,113,268				2,363,725	2,113,268	1,937,688
Purchase of property, plant and equipment									(15,607)	(27,896)	(38,969)
Goodwill	410,022				410,021				410,022	410,021	409,520
Swiss Operations Segment
Revenues									139,499	134,064	133,925
Revenue Transactions With Other Operating Segments									657,678	628,529	563,083
Net Sales									797,177	762,593	697,008
Segment Profit									233,292	202,027	174,447
Depreciation									6,069	5,835	5,551
Assets	1,648,065				1,471,625				1,648,065	1,471,625	1,374,150
Purchase of property, plant and equipment									(5,820)	(1,123)	(19,589)
Goodwill	22,369				21,994				22,369	21,994	22,171
Western European Operations Segment
Revenues									700,741	718,788	673,776
Revenue Transactions With Other Operating Segments									175,759	176,995	170,820
Net Sales									876,500	895,783	844,596
Segment Profit									123,845	122,574	123,841
Depreciation									4,450	4,173	4,052
Assets	1,150,214				983,809				1,150,214	983,809	1,805,294
Purchase of property, plant and equipment									(11,267)	(16,879)	(7,094)
Goodwill	87,980				87,242				87,980	87,242	91,927
Chinese Operations Segment
Revenues									544,716	525,109	452,617
Revenue Transactions With Other Operating Segments									224,517	242,452	232,882
Net Sales									769,233	767,561	685,499
Segment Profit									266,522	270,668	231,860
Depreciation									8,045	7,869	7,168
Assets	694,903				1,237,248				694,903	1,237,248	1,068,811
Purchase of property, plant and equipment									(10,252)	(13,248)	(13,246)
Goodwill	633				644				633	644	690
Other Operations Segment
Revenues									566,581	549,827	519,910
Revenue Transactions With Other Operating Segments									5,890	6,543	7,934
Net Sales									572,471	556,370	527,844
Segment Profit									71,483	78,317	72,681
Depreciation									3,395	3,774	3,474
Assets	358,281				319,070				358,281	319,070	310,667
Purchase of property, plant and equipment									(4,936)	(8,342)	(4,131)
Goodwill	14,975				14,879				14,975	14,879	15,530
Eliminations and Corporate Segment
Revenues									0	0	0
Revenue Transactions With Other Operating Segments									(1,178,638)	(1,158,977)	(1,073,836)
Net Sales									(1,178,638)	(1,158,977)	(1,073,836)
Segment Profit									(127,197)	(104,696)	(127,952)
Depreciation									6,348	5,091	5,554
Assets	(3,425,867)				(3,506,173)				(3,425,867)	(3,506,173)	(3,946,805)
Purchase of property, plant and equipment									(49,459)	(75,238)	(44,397)
Goodwill	$ 0				$ 0				$ 0	$ 0	$ 0