Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 2,586,528	$ 2,439,438
Accumulated Depreciation	(991,229)	(892,601)
Property, Plant, and Equipment, net	1,595,299	1,546,837
Land And Quarries [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	423,543	402,698
Plants [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,871,213	1,820,908
Buildings Machinery And Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	187,484	175,526
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 104,288	$ 40,306