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Financing: Term Loan (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Feb. 24, 2021	Mar. 31, 2021	Sep. 30, 2021	Sep. 30, 2020
Repayments of Other Short-term Debt			$ 800,000	$ 0
Senior Unsecured Notes Due 2021 | Line of Credit
Debt Instrument, Term	9 months
Debt Instrument, Face Amount	$ 800,000
Payment for Debt Extinguishment or Debt Prepayment Cost			$ 0
Repayments of Other Short-term Debt		$ 200,000

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Face (par) amount of debt instrument at time of issuance.

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