Schedule of Pension Plans Weighted-Average Asset Allocation and Range of Target Allocation (Detail) |
12 Months Ended | |
---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
|
Defined Benefit Plan Disclosure [Line Items] | ||
Percentage of Plan Assets at March 31 | 100.00% | 100.00% |
Equity Securities [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Range of Target Allocation - Minimum | 40.00% | |
Range of Target Allocation - Maximum | 60.00% | |
Percentage of Plan Assets at March 31 | 70.00% | 66.00% |
Debt Securities [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Range of Target Allocation - Minimum | 35.00% | |
Range of Target Allocation - Maximum | 60.00% | |
Percentage of Plan Assets at March 31 | 27.00% | 33.00% |
Other [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Range of Target Allocation - Minimum | 0.00% | |
Range of Target Allocation - Maximum | 5.00% | |
Percentage of Plan Assets at March 31 | 3.00% | 1.00% |