Equity Method Investments and Related-Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Schedule of Equity Method Investments [Line Items]
Foreign currency translation adjustments, net of tax		$ (1,436)	$ (7,104)	$ (3,720)	$ (6,901)
Income from equity method investments		1,154	314	$ 2,521	1,379
Euro Infrastructure Co [Member]
Schedule of Equity Method Investments [Line Items]
Payments, net of transaction costs, to acquire the issued shares in investment	$ 139,500
Equity method investment ownership percentage	49.00%
Foreign currency translation adjustments, net of tax		1,700	$ (7,000)		(3,500)
Maximum useful life of intangible assets basis difference, years				11 years
Weighted average useful life of intangible assets basis difference, years				10 years
Maximum useful life of tangible assets basis difference, years				11 years
Weighted average useful life of tangible assets basis difference, years				11 years
Income from equity method investments		1,200		$ 2,500	$ 1,400
Retained earnings of undistributed cumulative earnings in equity interests, net of tax		$ 9,000		$ 9,000