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Long-Term Debt (Credit Agreement) (Details) - Credit Agreement [Member] - USD ($) $ in Millions | Jul. 24, 2018 | Mar. 31, 2021
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Line of Credit | Minimum [Member] |  |
Debt Instrument [Line Items] |  |
Line of credit permitted increase | $ 25 |
Line of Credit | Maximum [Member] |  |
Debt Instrument [Line Items] |  |
Line of credit permitted increase | 500 |
Revolving Credit Facility [Member] |  |
Debt Instrument [Line Items] |  |
Remaining borrowing capacity |  | $ 1,000
Revolving Credit Facility [Member] | Line of Credit |  |
Debt Instrument [Line Items] |  |
Maximum borrowing capacity |  | 1,000
Line of Credit Facility, Fair Value of Amount Outstanding |  | 0
Outstanding letters of credit |  | $ 0
Letter of Credit [Member] | Line of Credit |  |
Debt Instrument [Line Items] |  |
Maximum borrowing capacity | 150 |
Swingline Loan [Member] | Line of Credit |  |
Debt Instrument [Line Items] |  |
Maximum borrowing capacity | $ 50 |
Alternate Base Rate [Domain] | Revolving Credit Facility [Member] | Line of Credit | Minimum [Member] |  |
Debt Instrument [Line Items] |  |
Spread on variable rate | 0.00% |
Alternate Base Rate [Domain] | Revolving Credit Facility [Member] | Line of Credit | Maximum [Member] |  |
Debt Instrument [Line Items] |  |
Spread on variable rate | 0.75% |
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Line of Credit | Minimum [Member] |  |
Debt Instrument [Line Items] |  |
Spread on variable rate | 1.00% |
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Line of Credit | Maximum [Member] |  |
Debt Instrument [Line Items] |  |
Spread on variable rate | 1.75% |

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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
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Balance Type: | na
Period Type: | duration

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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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Data Type: | xbrli:stringItemType
Balance Type: | na
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- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Fair value of the amount outstanding under the credit facility. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611 + Details
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Balance Type: | credit
Period Type: | instant

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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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Balance Type: | credit
Period Type: | instant

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- Definition The permitted amount the line of credit facility may be increased by, under certain circumstances if certain lenders agree to commit to such an increase. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Details
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- Details
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- Details
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- Details
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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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- Details
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- Details
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- Details
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