Goodwill and Intangible Assets (Carrying Value of Goodwill) (Detail) - USD ($)		3 Months Ended				12 Months Ended
	Oct. 01, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Goodwill [Roll Forward]
Beginning balance					$ 641,191,000	$ 416,418,000	$ 641,191,000
Translation adjustments						1,909,000	(501,000)
Impairment charge	$ 0	$ 0	$ 0	$ (224,272,000)	0	0	(224,272,000)	$ 0
Ending balance		416,418,000				418,327,000	416,418,000	641,191,000
Goodwill									$ 642,599,000
Accumulated impairment									(224,272,000)
Total		$ 416,418,000			$ 641,191,000	$ 418,327,000	$ 641,191,000	$ 641,191,000	$ 418,327,000