Restricted Investments	9 Months Ended
	Sep. 30, 2020
Restricted Investments Note [Abstract]
Restricted Investments	Restricted Investments.    Restricted investments consist of funds on deposit with the Rural Utilities Service in the Cushion of Credit Account that are held by the U.S. Treasury, acting through the Federal Financing Bank. We can only utilize these investments for future Rural Utilities Service-guaranteed Federal Financing Bank debt service payments. The funds on deposit as of September 30, 2020 earned interest at a rate of 5% per annum. Beginning October 1, 2020, deposits earn interest at 4% per annum and beginning October 1, 2021, the rates will be set at the 1-year floating treasury rate. The program no longer allows additional funds to be deposited into the account. At September 30, 2020 and December 31, 2019, we had restricted investments totaling $540,871,000 and $533,590,000, respectively, of which $301,163,000 and $461,757,000, respectively, were classified as long-term.