Expiration Years of Minimum Alternate Tax Credit (Detail) (Minimum Alternate Tax (MAT), USD $) In Millions, unless otherwise specified	Mar. 31, 2014
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	$ 22.11
2017-18
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	0.22
2018-19
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	0.30
2019-20
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	1.09
2020-21
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	5.50
2021-22
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	0.88
2022-23
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	6.63
2023-24
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	$ 7.49