Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Weighted Average Actuarial Assumptions Used to Determine Benefit Obligation (Detail)

v3.8.0.1
Employee Benefit Plans - Weighted Average Actuarial Assumptions Used to Determine Benefit Obligation (Detail) - Pension Plans, Defined Benefit [Member]
Mar. 31, 2018
Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]    
Discount rate 3.95% 4.08%
Rate of increase in compensation levels 3.00% 3.00%