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Other operating income (expense) - Additional Information (Detail) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2019 USD ($) | Sep. 30, 2019 USD ($) | Dec. 31, 2019 USD ($) InsuranceCarrier | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($)
Component Of Other Income And Expense [Line Items] |  |  |  |  |
Number of insurance carriers for which agreed to reimburse litigation costs | InsuranceCarrier |  |  | 1 |  |
Other income, net |  |  | $ 7,444 | $ 644 | $ 170
Proceeds from sale of business |  |  | 2,925 |  |
Gain from sale of business |  |  | $ 3,000 |  |
Insurance and Risk Management Business |  |  |  |  |
Component Of Other Income And Expense [Line Items] |  |  |  |  |
Proceeds from sale of business | $ 3,250 |  |  |  |
Gain from sale of business | $ 3,000 |  |  |  |
Sale of Excess Property |  |  |  |  |
Component Of Other Income And Expense [Line Items] |  |  |  |  |
Other income, net |  | $ 4,400 |  |  |

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- Definition Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109239629&loc=SL4582445-111684 + Details
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- Definition The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585 + Details
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