Derivative Instruments - Effects of Gains and Losses from Derivative Instruments (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivatives	$ 186		$ (352)		$ 18
Cost of Sales | Derivatives designated as fair value hedges | Put Option
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivatives	217		(339)		41
Cost of Sales | Derivatives not designated as hedging instruments | Put Option
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivatives	(28)		27
Propane Inventory | Derivatives designated as fair value hedges | Put/Call Option
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivatives	97		0		(23)
Revenue | Forward Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivatives	217		(339)		41
Revenue | Derivatives not designated as hedging instruments | Forward Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivatives	$ (100)	[1]	$ (40)	[1]	$ 0	[1]

[1] As a fair value hedge with no ineffective portion, the unrealized gains and losses associated with this call option are recorded in cost of sales, offset by the corresponding change in the value of propane inventory (hedged item), which is also recorded in cost of sales. The amounts in cost of sales offset to zero and the unrealized gains and losses of this call option effectively changed the value of propane inventory.