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Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | ---
Sep. 30, 2021 | Mar. 31, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020 | Dec. 31, 2020 | Dec. 31, 2019
Income Tax Disclosure [Line Items] |  |  |  |  |  |  |
Effective tax rate expense (benefit) | 14.10% |  | 9.30% | 354.50% | (36.80%) |  |
Income tax benefit, result of CARES act of 2020 |  |  |  |  | $ 7,800 |  |
Income tax expense, result of Alabama business tax competitiveness act |  | $ 1,600 |  |  |  |  |
Unrecognized tax benefits | $ 18,178 |  |  | $ 18,178 |  | $ 1,078 | $ 1,487
Deferred tax assets, gross | 59,189 |  |  | 59,189 |  | 55,687 |
Valuation allowance established against deferred tax assets | 50,232 |  |  | 50,232 |  | 45,818 |
Deferred tax assets | 8,957 |  |  | 8,957 |  | 9,869 |
Unrecognized tax benefits, effective tax rate | 18,100 |  |  | 18,100 |  | 1,000 |
Accrued interest and penalties | 300 |  |  | 300 |  | 300 |
IRS [Member] |  |  |  |  |  |  |
Income Tax Disclosure [Line Items] |  |  |  |  |  |  |
Income tax refund receivable | 15,200 |  |  | 15,200 |  |  |
Deferred tax asset, research and development credit carryforwards | 1,800 |  |  | 1,800 |  |  |
Unrecognized tax benefits | 17,000 |  |  | 17,000 |  |  |
Domestic [Member] |  |  |  |  |  |  |
Income Tax Disclosure [Line Items] |  |  |  |  |  |  |
Deferred tax assets, gross | 47,839 |  |  | 47,839 |  | 43,791 |
Valuation allowance established against deferred tax assets | 47,839 |  |  | 47,839 |  | 43,791 |
Increase in deferred tax asset valuation allowance |  |  |  | 4,000 |  |  |
International [Member] |  |  |  |  |  |  |
Income Tax Disclosure [Line Items] |  |  |  |  |  |  |
Deferred tax assets, gross | 11,350 |  |  | 11,350 |  | 11,896 |
Valuation allowance established against deferred tax assets | 2,393 |  |  | 2,393 |  | 2,027 |
Deferred tax assets | $ 8,957 |  |  | 8,957 |  | $ 9,869 |
Increase in deferred tax asset valuation allowance |  |  |  | $ 400 |  |  |

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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. + 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 (b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
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- Definition Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + 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 The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + Details
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