Regulatory Assets and Liabilities and Regulatory Matters - Additional Information (Details) - USD ($) $ in Thousands																	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Oct. 27, 2018	Oct. 25, 2018	Jun. 30, 2018	May 17, 2018	Jan. 26, 2018	Oct. 20, 2017	Jul. 02, 2017	Jul. 01, 2017	Jan. 19, 2017	Jan. 01, 2017	Oct. 19, 2016	Oct. 14, 2016	Jun. 30, 2016	Apr. 01, 2016	Jan. 19, 2016	Apr. 01, 2015	Mar. 31, 2016	Jun. 30, 2018	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2014
Regulatory Assets
Unrealized gains (losses) on derivative financial instruments contracts																				$ 2,856	$ 146
PUC Temporary Rates Order, Reduction In Revenue																		$ 24,098		$ 24,430	$ 0	$ 0
Public utilities, civil penalties							$ 2,100
Capitalized project costs																						5,830
Project costs expensed in prior periods																						5,375
Information Technology
Regulatory Assets
Associated increase to utility property, plant and equipment																						2,755
Subsequent Event
Regulatory Assets
Period to recover costs related to regulatory assets	20 years
UGI South
Regulatory Assets
PUC temporary rates order, percent of reduction in base rate revenues				5.78%
UGI North
Regulatory Assets
PUC temporary rates order, percent of reduction in base rate revenues				3.90%
UGI Central
Regulatory Assets
PUC temporary rates order, percent of reduction in base rate revenues				8.19%
Pennsylvania Public Utility Commission
Regulatory Assets
Requested operating revenue increase					$ 9,200				$ 21,700
Distribution system improvement charge, percent of amount billed to customers																							0.00%
Pennsylvania Public Utility Commission | Electric Utilities
Regulatory Assets
Requested operating revenue increase			$ 7,700
Pennsylvania Public Utility Commission | Electric Utilities | Subsequent Event
Regulatory Assets
Public utilities, requested increase in annual base distribution revenues		$ 3,201
Tax Cuts And Jobs Act Of 2017, customer billing credit	$ 210
Pennsylvania Public Utility Commission | PNG
Regulatory Assets
Approved operating revenue increase						$ 11,250
Distribution system improvement charge, percent of amount billed to customers								7.50%								0.00%
Pennsylvania Public Utility Commission | UGI Gas
Regulatory Assets
Requested operating revenue increase															$ 58,600
Amount of operating revenue increase													$ 27,000
Approved operating revenue increase												$ 27,000
Pennsylvania Public Utility Commission | CPG
Regulatory Assets
Distribution system improvement charge, percent of amount billed to customers								7.50%						0.00%
Removal Costs
Regulatory Assets
Period to recover costs related to regulatory assets																				5 years
Deferred Project Costs
Regulatory Assets
Associated increase to utility regulatory assets																						$ 3,075
Income Tax Benefits
Regulatory Assets
PUC Temporary Rates Order, Reduction In Revenue																			$ 17,135
Future Amortization Of Regulatory Liabilities
Regulatory Assets
PUC Temporary Rates Order, Reduction In Revenue																			$ 6,963
Minimum
Regulatory Assets
Average remaining depreciable lives of the associated property																			1 year	1 year
Maximum
Regulatory Assets
Average remaining depreciable lives of the associated property																			65 years	65 years
Maximum | Pennsylvania Public Utility Commission
Regulatory Assets
Distribution system improvement charge, percent of amount billed to customers										5.00%
Maximum | Pennsylvania Public Utility Commission | CPG
Regulatory Assets
Distribution system improvement charge, percent of amount billed to customers																	10.00%
Maximum | Postretirement benefits overcollections
Regulatory Assets
Regulatory liability, period over which overcollections will be refunded to customers											10 years