Risk Management (Notional Amounts and Terms of Company's Derivative Financial Instruments) (Details) - Propane Crude And Heating Oil - bbl bbl in Millions	Mar. 31, 2016	Dec. 31, 2015
Fixed Price Payor
Derivative [Line Items]
Derivative, notional amount	10.6	9.1
Fixed Price Receiver
Derivative [Line Items]
Derivative, notional amount	11.9	10.9

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

Name:	invest_DerivativeNonmonetaryNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant