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Fair Value Measurement - Additional Information (Detail)
₨ in Millions, $ in Millions
Mar. 31, 2018
INR (₨)
Mar. 31, 2018
USD ($)
Mar. 31, 2017
INR (₨)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments, at cost ₨ 708.4 $ 10.9 ₨ 708.2
Available-for-Sale Securities      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-Sale securities classified as level 1 transferred to level 2     ₨ 6,600.0