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Equity - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2020
Class A Common Stock [Member] |
Class of Stock [Line Items] |
Common stock, voting right | Class A common stock entitles the holder to one vote for each share
Class B Common Stock [Member] |
Class of Stock [Line Items] |
Common stock, voting right | Class B common stock entitles the holder to ten votes for each share
Common stock, conversion features | Each share of Class B common stock is convertible into one share of Class A common stock at the option of the holder at any time. Automatic conversion shall occur upon the occurrence of a transfer of such share of Class B common stock or at the date and time, or the occurrence of an event, specified by a vote or written consent of the holders of a majority of the voting power of the then outstanding shares of Class B common stock.​​​​​​​ A transfer is described as a sale, assignment, transfer, conveyance, hypothecation or disposition of such share or any legal or beneficial interest in such share other than certain permitted transfers as described in the Restated Certificate of Incorporation, including a transfer to a holder of Preferred Stock. Each share of Class B common stock held by a stockholder shall automatically convert into one fully paid and non-assessable share of Class A common stock nine months after the death or incapacity of the holder of such Class B common stock.​​​​​​​

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- Definition Description of common stock conversion feature. Includes, but is not limited to, conversion price; conversion right; timing of right; terms, event or change in circumstance causing contingency to be met or adjustment to conversion price or number of shares; manner of settlement upon conversion; and method of settlement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644 + Details
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- Definition Description of voting rights of common stock. Includes eligibility to vote and votes per share owned. Include also, if any, unusual voting rights. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 + Details
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