Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Stock-Based Compensation - Assumptions Used for Restricted Stock Grants (Detail)

v3.7.0.1
Stock-Based Compensation - Assumptions Used for Restricted Stock Grants (Detail) - Restricted Stock Units (Market Condition) [Member] - AUD / shares
12 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Date of grant Sep. 16, 2016 Sep. 16, 2015
Dividend yield (per annum) 2.30% 3.80%
Expected volatility 31.50% 36.80%
Risk free interest rate 1.10% 1.50%
Expected life in years 3 years 3 years
JHX stock price at grant date (A$) AUD 20.82 AUD 17.76
Number of restricted stock units 456,819 579,262