Total costs accrued as of the balance sheet date for environmental loss contingencies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346

Name:	us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Commitments and Contingencies - Contingencies (Details) $ in Thousands		12 Months Ended
	Jul. 02, 2017 USD ($)	Sep. 30, 2018 USD ($) subsidiary	Sep. 30, 2017 USD ($)
Contingencies
Public utilities, civil penalties	$ 2,100
CPG; PNG and UGI Gas COAs
Contingencies
Accrued liabilities for environmental investigation and remediation costs		$ 50,970	$ 54,250
Environmental Issue \| CPG; PNG and UGI Gas COAs
Contingencies
Environmental expenditures cap during calendar year		$ 5,000
PNG and CPG
Contingencies
Number of subsidiaries acquired with similar histories \| subsidiary		2