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Fair Value Measurements Fair Value Measurements (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Assets, Fair Value Disclosure [Abstract] |  |
Money Market Funds | $ 579,105 | $ 551,213
US Government Securities, at Carrying Value | 5,782 | 10,531
Municipal bonds | 26,009 | 23,998
Total | 610,896 | 585,742
US Treasury Securities [Member] |  |
Debt Securities, Available-for-sale [Abstract] |  |
Available-for-sale Securities, Amortized Cost Basis | 5,783 | 10,530
Available-for-sale Securities, Gross Unrealized Gain | 0 | 1
Available-for-sale Securities, Gross Unrealized Loss | (1) | 0
Fair Value | 5,782 | 10,531
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] |  |
Fair Value | 5,782 | 10,531
Municipal Bond [Member] |  |
Debt Securities, Available-for-sale [Abstract] |  |
Available-for-sale Securities, Amortized Cost Basis | 26,017 | 23,994
Available-for-sale Securities, Gross Unrealized Gain | 0 | 8
Available-for-sale Securities, Gross Unrealized Loss | (8) | (4)
Fair Value | 26,009 | 23,998
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] |  |
Fair Value | 26,009 | 23,998
Level 1 [Member] |  |
Assets, Fair Value Disclosure [Abstract] |  |
Money Market Funds | 579,105 | 551,213
US Government Securities, at Carrying Value | 5,782 | 10,531
Municipal bonds | 0 | 0
Total | 584,887 | 561,744
Level 2 [Member] |  |
Assets, Fair Value Disclosure [Abstract] |  |
Money Market Funds | 0 | 0
US Government Securities, at Carrying Value | 0 | 0
Municipal bonds | 26,009 | 23,998
Total | $ 26,009 | $ 23,998

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- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References No definition available. + Details
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- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
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- Definition Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
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- Definition Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References No definition available. + Details
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Debt (bills, notes or bonds) that are issued by the government of the United States which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. + References No definition available. + Details
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