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Commitments and contingencies - Additional Information (Narrative) (Details) | Dec. 31, 2020 USD ($)
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Loss Contingencies [Line Items] |
Auction Rate Securities Committed To Purchase related to settlements with regulators | $ 1,300,000
Equity Securities [Member] |
Loss Contingencies [Line Items] |
Contractual Obligation | 40,000,000.0
Private Equity Funds [Member] |
Loss Contingencies [Line Items] |
Contractual Obligation | 1,200,000
Minimum [Member] |
Loss Contingencies [Line Items] |
Maximum estimated range of aggregate loss for legal proceedings | 0
Maximum [Member] |
Loss Contingencies [Line Items] |
Maximum estimated range of aggregate loss for legal proceedings | $ 5,000,000.0

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- Definition Auction Rate Securities Committed To Purchase related to settlements with regulators + References No definition available. + Details
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- Definition Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments. + References No definition available. + Details
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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. + References No definition available. + Details
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- Definition The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 05 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=99385795&loc=d3e12631-108344 + Details
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