Share Based Compensation - Assumptions Used in the Black-Scholes Option Pricing Model to Estimate the Fair Value of Each Stock Option Grant (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Risk-free interest rate, Minimum	0.27%
Risk-free interest rate, Maximum	0.31%
Expected volatility, Minimum	46.90%
Expected volatility, Maximum	52.20%
Weighted average grant-date fair value per share of options granted	$ 8.38
Cash received from exercise of options (in thousands)	$ 2,077	$ 92
Minimum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Expected life	4 years 3 months 18 days
Maximum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Expected life	5 years 4 months 24 days

Amount of cash inflow from exercise of option under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=SL79508275-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
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The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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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.

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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-SubTopic 10
-Section 50
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-Name Accounting Standards Codification
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