Deferred Revenue and Customer Advances (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred Revenue Arrangement
Maintenance, service and training	$ 63,815	$ 58,362
Extended warranty	30,677	27,422	$ 24,438	$ 28,200
Customer advances, undelivered elements and other	56,358	24,677
Total deferred revenue and customer advances	$ 150,850	$ 110,461