Goodwill and Identifiable Intangible Assets - Activity in Goodwill Balance (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Goodwill [Roll Forward]
Balance at beginning of period	$ 912,170	$ 839,301	$ 906,962	$ 884,185
Effect of foreign currency translation	2,897	(1,277)	8,105	(46,161)
Balance at end of period	$ 915,067	$ 838,024	$ 915,067	$ 838,024