Segment Information (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Information [Abstract]
Company's Segment Information, Continuing Operations	Three Months Ended Three Months Ended September 30, 2021 September 30, 2020 Regulated Water Regulated Natural Gas Other Consolidated Regulated Water Regulated Natural Gas Other ConsolidatedOperating revenues $ 259,859  $ 94,752  $ 7,249  $ 361,860  $ 255,725  $ 88,880  $ 4,042  $ 348,647 Operations and maintenance expense 86,923  53,954  (1,522) 139,355  79,313  59,560  (2,699) 136,174 Purchased gas - 20,386  5,102  25,488  - 14,841  1,903  16,744 Depreciation and amortization 45,506  28,194  807  74,507  42,955  25,793  1,193  69,941 Taxes other than income taxes 16,291  4,271  496  21,058  15,906  4,145  504  20,555 Operating income (loss) 111,139  (12,053) 2,366  101,452  117,551  (15,459) 3,141  105,233 Interest expense, net 27,389  18,406  5,772  51,567  27,063  9,333  13,351  49,747 Allowance for funds used during construction (5,407) (675) - (6,082) (3,082) (461) - (3,543)Equity loss in joint venture - - - - - - 3,626  3,626 Other (1,896) 5,329  266  3,699  110  (761) (3,709) (4,360)Income before income taxes 91,053  (35,113) (3,672) 52,268  93,460  (23,570) (10,127) 59,763 Provision for income taxes (benefit) 9,230  (6,821) (644) 1,765  8,081  (1,219) (2,831) 4,031 Net income (loss) $ 81,823  $ (28,292) $ (3,028) $ 50,503  $ 85,379  $ (22,351) $ (7,296) $ 55,732  Nine Months Ended Nine Months Ended September 30, 2021 September 30, 2020 Regulated Water Regulated Natural Gas Other Consolidated Regulated Water Regulated Natural Gas Other ConsolidatedOperating revenues $ 736,389  $ 579,429  $ 26,639  $ 1,342,457  $ 706,008  $ 273,798  $ 8,894  $ 988,700 Operations and maintenance expense 243,071  157,614  (8,740) 391,945  229,652  120,192  21,571  371,415 Purchased gas - 183,062  19,476  202,538  - 68,807  4,127  72,934 Depreciation and amortization 136,189  83,905  1,529  221,623  127,214  56,026  2,838  186,078 Taxes other than income taxes 47,756  13,356  2,107  63,219  45,292  8,799  2,333  56,424 Operating income (loss) 309,373  141,492  12,267  463,132  303,850  19,974  (21,975) 301,849 Interest expense, net 80,971  56,125  16,551  153,647  78,500  21,260  31,544  131,304 Allowance for funds used during construction (13,091) (831) - (13,922) (7,905) (816) - (8,721)Equity loss in joint venture - - - - - - 3,283  3,283 Other (5,265) 4,462  (1,213) (2,016) 477  (1,516) (2,489) (3,528)Income before income taxes 246,758  81,736  (3,071) 325,423  232,778  1,046  (54,313) 179,511 Provision for income taxes (benefit) 22,056  (11,128) (611) 10,317  18,402  (8,131) (12,902) (2,631)Net income (loss) $ 224,702  $ 92,864  $ (2,460) $ 315,106  $ 214,376  $ 9,177  $ (41,411) $ 182,142 Capital expenditures $ 404,894  $ 269,958  $ 993  $ 675,845  $ 376,064  $ 134,632  $ 43,445  $ 554,141
Company's Segment Information, Assets	September 30, December 31, 2021 2020Total assets: Regulated water $ 8,301,201 $ 7,838,034Regulated natural gas 5,748,774 5,303,507Other 186,510 563,736Consolidated $ 14,236,485 $ 13,705,277