Contractual Maturities of Investments in Debt Securities Held (Detail) $ in Thousands	Apr. 01, 2018 USD ($)
Schedule of Available-for-sale Securities
Due within one year, cost	$ 861,794
Due after 1 year through 5 years, cost	10,173
Due after 5 years through 10 years, cost	14,583
Due after 10 years, cost	40,036
Total, cost	926,586
Due within one year, fair market value	860,526
Due after 1 year through 5 years, fair market value	10,058
Due after 5 years through 10 years, fair market value	13,823
Due after 10 years, fair maket value	40,024
Total, fair market value	$ 924,431