In Thousands, unless otherwise specified | Amortizing Secured Note, due December 20, 2021 [Member] | Amortizing Secured Note, due May 19, 2028 [Member] | Amortizing Secured Note, due August 25, 2030 [Member] | Amortizing Secured Note, due September 19, 2031 [Member] | State Revolving Trust Note, due December 31, 2022 [Member] | State Revolving Trust Note, due March 1, 2026 [Member] | State Revolving Trust Note, due January 25, 2027 [Member] | State Revolving Trust Note, due December 1, 2026 [Member] | State Revolving Trust Bond, due August 1, 2021 [Member] | State Revolving Trust Note, due May 1, 2025 [Member] | State Revolving Trust Note, due July 1, 2028 [Member] | State Revolving Trust Note, due January 1, 2028 [Member] | State Revolving Trust Note, due August 1, 2031 [Member] | Amortizing Secured Note, due April 20, 2029 [Member] | Amortizing Secured Note, due January 20, 2030 [Member] | Amortizing Secured Note, due January 20, 2030 [Member] | State Revolving Trust Note, due July 1, 2031 [Member] | State Revolving Trust Note, due November 30, 2030 [Member] | First Mortgage Bonds - Series X [Member] | First Mortgage Bonds - Series Z [Member] | First Mortgage Bonds - Series BB [Member] | First Mortgage Bonds - Series EE [Member] | First Mortgage Bonds - Series GG [Member] | First Mortgage Bonds - Series II [Member] | First Mortgage Bonds - Series KK [Member] | First Mortgage Bonds - Series MM [Member] | First Mortgage Bonds - Series OO [Member] | First Mortgage Bonds - Series QQ [Member] | First Mortgage Bonds - Series RR [Member] | First Mortgage Bonds - Series SS [Member] | First Mortgage Bonds - Series TT [Member] | State Revolving Trust Bond, due August 1, 2021 [Member] | First Mortgage Bonds - Series Y [Member] | First Mortgage Bonds - Series AA [Member] | First Mortgage Bonds - Series CC [Member] | First Mortgage Bonds - Series FF [Member] | First Mortgage Bonds - Series HH [Member] | First Mortgage Bonds - Series JJ [Member] | First Mortgage Bonds - Series LL [Member] | First Mortgage Bonds - Series NN [Member] | First Mortgage Bonds - Series PP [Member] | First Mortgage Bonds - Series UU [Member] | First Mortgage Bonds - Series VV [Member] | First Mortgage Bonds - Series WW [Member] | Convertible Preferred Stock $7.00 Series [Member] | Convertible Preferred Stock $7.00 Series [Member] | Convertible Preferred Stock $8.00 Series [Member] | Convertible Preferred Stock $8.00 Series [Member] | Nonredeemable Preferred Stock $7.00 Series [Member] | Nonredeemable Preferred Stock $7.00 Series [Member] | Nonredeemable Preferred Stock $4.75 Series [Member] | Nonredeemable Preferred Stock $4.75 Series [Member] |