Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 88,565	$ 157,042	$ 76,917
Other Comprehensive Income (Loss), Net of Tax:
Postretirement Liability Adjustment, net of tax	11,455	(5,692)	(6,498)
Reclassification of Unrealized Gain on Derivatives - Other to Net Income, net of tax	32	34	35
Other Comprehensive Income (Loss) - Net of Tax	11,487	(5,658)	(6,463)
Comprehensive Income	100,052	151,384	70,454
Subtract/Add: Comprehensive Income (Loss) Attributable to Noncontrolling Interests	474	(42)	0
Comprehensive Income Attributable to South Jersey Industries, Inc.	$ 99,578	$ 151,426	$ 70,454