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Equity Method Investments and Related-Party Transactions - Additional Information (Detail) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Mar. 31, 2017
Mar. 31, 2021
Apr. 30, 2021
Euro​ Infrastructure​ Co Step Acquisition [Member]      
Schedule of Equity Method Investments [Line Items]      
Percentage of additional interest in subsidiary acquired     51.00%
Euro Infrastructure Co [Member]      
Schedule of Equity Method Investments [Line Items]      
Payments, net of transaction costs, to acquire the issued shares in investment $ 139.5    
Equity method investment ownership percentage 49.00%    
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  
Retained earnings of undistributed cumulative earnings in equity interests, net of tax     $ 10.4