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Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 | Dec. 31, 2018 | Dec. 31, 2019
Income Tax Contingency [Line Items] |  |  |
Gross unrecognized tax benefits, effective tax rate reduced | $ 5,900 |  |
Decrease in valuation allowance |  | $ 13,500 |
Valuation allowance for deferred tax asset | 12,892 |  | $ 13,578
Net operating loss carryforwards, valuation allowance | 7,200 |  |
Undistributed earnings of subsidiaries | 209,800 |  |
Unrecognized deferred income tax liabilities | 10,500 |  |
Federal |  |  |
Income Tax Contingency [Line Items] |  |  |
Federal capital losses | 7,200 |  |
Net operating loss carryforwards, valuation allowance | 5,700 |  |
Net operating loss carryforwards | 6,800 |  |
State |  |  |
Income Tax Contingency [Line Items] |  |  |
Net operating loss carryforwards, valuation allowance | 7,200 |  |
Net operating loss carryforwards | $ 8,600 |  |

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- Definition Tax Cuts And Jobs Act, Incomplete Accounting, Change In Tax Rate, Valuation Allowance, Provisional Income Tax Benefit + References No definition available. + Details
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible capital loss carryforwards. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319 + Details
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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
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- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319 + Details
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