Schedule of Inventories (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Inventory [Line Items]
Inventories	$ 235,464	$ 187,096
Raw Materials and Material-in-Progress [Member]
Inventory [Line Items]
Inventories	115,345	82,319
Finished Cement [Member]
Inventory [Line Items]
Inventories	20,508	19,173
Gypsum Wallboard [Member]
Inventory [Line Items]
Inventories	7,741	7,144
Paperboard [Member]
Inventory [Line Items]
Inventories	8,493	4,102
Frac Sand [Member]
Inventory [Line Items]
Inventories	4,928	275
Aggregates [Member]
Inventory [Line Items]
Inventories	11,131	11,815
Repair Parts and Supplies [Member]
Inventory [Line Items]
Inventories	62,121	56,119
Fuel and Coal [Member]
Inventory [Line Items]
Inventories	$ 5,197	$ 6,149