Regulatory Assets and Liabilities and Regulatory Matters - Regulatory Assets and Liabilities Associated with Gas Utility and Electric Utility (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Sep. 30, 2015
Regulatory Assets and Liabilities
Regulatory assets		$ 395,141	$ 304,208
Regulatory liabilities	[1]	55,569	71,004
Postretirement Benefits Overcollections
Regulatory Assets and Liabilities
Regulatory liabilities	[1]	17,519	19,975
Deferred Fuel and Power Refunds
Regulatory Assets and Liabilities
Regulatory liabilities	[1]	22,299	36,638
State Income Tax Benefits — Distribution System Repairs
Regulatory Assets and Liabilities
Regulatory liabilities	[1]	15,086	13,266
Other
Regulatory Assets and Liabilities
Regulatory liabilities	[1]	665	1,125
Income Taxes Recoverable
Regulatory Assets and Liabilities
Regulatory assets		115,643	115,946
Underfunded Pension and Postretirement Plans
Regulatory Assets and Liabilities
Regulatory assets		183,129	140,762
Environmental Costs
Regulatory Assets and Liabilities
Regulatory assets	[2]	59,397	19,983
Removal Costs, Net
Regulatory Assets and Liabilities
Regulatory assets		27,956	21,223
Other
Regulatory Assets and Liabilities
Regulatory assets		$ 9,016	$ 6,294

[1] Regulatory liabilities, other than deferred fuel and power refunds, are recorded in other current and noncurrent liabilities in the Consolidated Balance Sheets.

[2] )Balance at September 30, 2016, includes amounts associated with UGI Gas’ Consent Order and Agreement with the Pennsylvania Department of Environmental Protection (see Note 12