Equity Plan - Information Related to the Equity Plans for each of the Last Three Years (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021
Information Related to the Equity Plans
Cash received from option exercise	$ 849	$ 784
Options
Information Related to the Equity Plans
Intrinsic value of options exercised	706,376	679,403
Cash received from option exercise	848,739	784,264
Tax benefit (expense) realized from option exercises	$ 52,952	$ 57,215
Weighted average fair value of options granted (in dollars per share)	$ 2.18	$ 2.33

Amount of tax benefit from exercise of option under share-based payment arrangement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2A
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=SL79508275-113901

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2A
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-URI https://asc.fasb.org/extlink&oid=128089324&loc=SL79508275-113901

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-Section 45
-Paragraph 14
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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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