Equity Method Investments and Related-Party Transactions - Schedule of Related Party Transactions (Detail) - Euro Infrastructure Co [Member] - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Related Party Transaction [Line Items]
Revenue	$ 4,599	$ 1,327	$ 8,352	$ 3,178
Expense	5,708	2,432	8,905	4,590
Cash received	1,490	3,624	2,352	6,054
Cash paid	4,462	$ 2,145	7,456	$ 4,092
Accounts receivable	4,520		4,520
Collections in excess of revenues and deferred revenues	1,397		1,397		$ 4,703
Accounts payable	$ 2,234		$ 2,234

Amount for accounts payable to related parties.

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