Equity Method Investments and Related-Party Transactions - Schedule of Related Party Transactions (Detail) - USD ($) $ in Thousands	3 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018
Euro Infrastructure Co [Member]
Related Party Transaction [Line Items]
Revenue	$ 1,851	$ 3,451
Expense	2,159	1,831
Cash received	2,430	2,071
Cash paid	1,947	$ 2,021
Accounts receivable	2,167		$ 3,307
Collections in excess of revenues and deferred revenues	3,607		3,246
Ducommun Inc. [Member]
Related Party Transaction [Line Items]
Cash paid	2,458
Accounts payable	$ 3,918		$ 2,073

Amount for accounts payable to related parties.

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