Information about Contract Liabilities (Detail) - USD ($) $ in Thousands	Apr. 01, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue and customer advances	$ 85,892		$ 83,614
Long-term deferred revenue and customer advances	21,726		$ 30,127
ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue and customer advances	90,882	$ 76,638
Long-term deferred revenue and customer advances	30,904	20,848
ASU 2014-09 | Adjustments to Recognize under Legacy GAAP
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue and customer advances	4,990	9,254
Long-term deferred revenue and customer advances	$ 9,178	$ 878