Goodwill and Intangible Assets - Schedule of Changes in Goodwill (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Net balance at January 1	$ 413,640,000	$ 422,185,000
Additions (Note 13)	19,917,000	0
Goodwill, Impairment Loss	0	0	$ 0
Disposal Group, Including Discontinued Operation, Goodwill		525,000
Currency translation	3,122,000	(8,020,000)
Net balance at December 31	436,679,000	$ 413,640,000	$ 422,185,000
Sordin
Goodwill [Roll Forward]
Goodwill, Impairment Loss	$ 0