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Asbestos - Numbers of Open Claims, New Claims and Closed Claims and Average Settlement Per Settled Claim and Case Closed (Detail) | 12 Months Ended |  |  |  |  |
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Mar. 31, 2019 USD ($) claim | Mar. 31, 2018 USD ($) claim | Mar. 31, 2017 USD ($) claim | Mar. 31, 2016 USD ($) claim | Mar. 31, 2015 USD ($) claim | Mar. 31, 2019 AUD ($) | Mar. 31, 2018 AUD ($) | Mar. 31, 2017 AUD ($) | Mar. 31, 2016 AUD ($) | Mar. 31, 2015 AUD ($)
Loss Contingency, Pending Claims, Number [Roll Forward] |  |  |  |  |  |  |  |  |  |
Number of open claims at beginning of period | 336 | 352 | 426 | 494 | 466 |  |  |  |  |
Number of new claims | 568 | 562 | 557 | 577 | 665 |  |  |  |  |
Number of closed claims | 572 | 578 | 631 | 645 | 637 |  |  |  |  |
Number of open claims at end of period | 332 | 336 | 352 | 426 | 494 |  |  |  |  |
Average settlement amount per settled claim | $ 191,236 | $ 196,093 | $ 168,300 | $ 182,763 | $ 222,619 | $ 262,108 | $ 253,431 | $ 223,535 | $ 248,138 | $ 254,209
Average settlement amount per case closed | $ 170,842 | $ 167,934 | $ 126,158 | $ 161,229 | $ 190,468 | $ 234,156 | $ 217,038 | $ 167,563 | $ 218,900 | $ 217,495

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- Definition The number of claims settled and dismissed during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349 + Details
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- Definition The total number of new claims filed pertaining to a loss contingency during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349 + Details
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