Employee Benefit Plans - Summary of Weighted Average Asset Allocation of Plan Assets by Asset Category (Detail) |
Mar. 31, 2018 |
Mar. 31, 2017 |
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| Defined Benefit Plan Disclosure [Line Items] | ||
| Weighted average asset allocation | 100.00% | 100.00% |
| Equity Securities [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Weighted average asset allocation | 67.00% | 68.00% |
| Equity Securities [Member] | Minimum [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Target Plan Asset Allocations | 50.00% | |
| Equity Securities [Member] | Maximum [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Target Plan Asset Allocations | 70.00% | |
| Debt Securities [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Weighted average asset allocation | 33.00% | 32.00% |
| Debt Securities [Member] | Minimum [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Target Plan Asset Allocations | 20.00% | |
| Debt Securities [Member] | Maximum [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Target Plan Asset Allocations | 50.00% |
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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