Remaining number of shares eligible for purchase under employee stock purchase plan.

No definition available.

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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.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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- Definition

Per share weighted-average price paid for shares purchased on open market for issuance under share-based payment arrangement.

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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

+ References

No definition available.

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- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

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- Definition

Aggregate change in value for stock issued during the period as a result of employee stock purchase plan.

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Equity Compensation Plans - 1996 Employee Stock Purchase Plan (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Value of stock purchases made pursuant to employee stock purchase plan	$ 2,227	$ 2,311	$ 1,776
1996 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for issue to employees under the employee stock purchase plan		1,700,000
Purchase Price of shares as a percentage of market value		85.00%
Number of shares purchased under employee stock purchase plan	54,949	68,902	50,674
Value of stock purchases made pursuant to employee stock purchase plan	$ 2,300	$ 2,400	$ 1,800
Remaining number of shares eligible for purchase under employee stock purchase plan	222,260
1996 Employee Stock Purchase Plan \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of shares under the plan		$ 30.76	$ 27.00	$ 31.88
1996 Employee Stock Purchase Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of shares under the plan		$ 48.99	$ 39.68	$ 41.14