Summary of Unbilled Receivables (Detail) $ in Thousands	Jun. 30, 2018 USD ($)
Accounts Receivable and Unbilled Receivable [Line Items]
1 Year or Less	$ 151,354
1-2 Years	79,654
2-5 Years	89,676
Total	$ 320,684

Amount of receivables under long-term contracts that have not been billed and were not billable that are expected to be collected in the next fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

Name:	us-gaap_UnbilledReceivablesNotBillableAtBalanceSheetDateAmountExpectedToBeCollectedWithinOneYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant