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Significant Accounting Policies - Investment Plan (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Defined Contribution Plan Disclosure [Line Items] |  |  |
Company's matching contribution, percentage | 6.00% |  |
Discretionary contributions to the Plan, amount | $ 0 | $ 0 | $ 0
Total payment and cost to the Plan | $ 2,976,000 | $ 3,460,000 | $ 3,205,000
Minimum |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Discretionary contributions to the Plan, percentage | 1.00% |  |
Maximum |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Discretionary contributions to the Plan, percentage | 6.00% |  |

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- Definition Defined Contribution Plan, Employer Discretionary Contribution Percent + References No definition available. + Details
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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + 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 Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
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