Goodwill and Intangible Assets, Net (Schedule of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Beginning balance	$ 239,724	$ 214,489	$ 199,873
Business combinations	220	24,826	20,282
Goodwill, Purchase Accounting Adjustments	1,900
Impact of changes in foreign currency exchange rates	5,303	409	(5,666)
Ending balance	243,347	239,724	214,489
Companion Animal Group Segment [Member]
Goodwill [Roll Forward]
Beginning balance	207,350	182,386	166,236
Business combinations	220	24,826	20,282
Goodwill, Purchase Accounting Adjustments	1,900
Impact of changes in foreign currency exchange rates	4,724	138	(4,132)
Ending balance	210,394	207,350	182,386
Water
Goodwill [Roll Forward]
Beginning balance	11,611	11,221	11,951
Business combinations	0	0	0
Goodwill, Purchase Accounting Adjustments	0
Impact of changes in foreign currency exchange rates	412	390	(730)
Ending balance	12,023	11,611	11,221
Livestock And Poultry Diagnostics Segment [Member]
Goodwill [Roll Forward]
Beginning balance	14,232	14,351	15,155
Business combinations	0	0	0
Goodwill, Purchase Accounting Adjustments	0
Impact of changes in foreign currency exchange rates	167	(119)	(804)
Ending balance	14,399	14,232	14,351
Other
Goodwill [Roll Forward]
Beginning balance	6,531	6,531	6,531
Business combinations	0	0	0
Goodwill, Purchase Accounting Adjustments	0
Impact of changes in foreign currency exchange rates	0	0	0
Ending balance	$ 6,531	$ 6,531	$ 6,531

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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