Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Common units issued	218,909,977		218,895,515
Common units outstanding	218,909,977		218,895,515
Accounts receivable, net	$ 97,890	[1]	$ 83,943	[1]
Other current assets	10,841	[2]	10,799	[2]
Accounts and natural gas imbalance payables	29,104	[3]	39,589	[3]
Accrued liabilities	158,730	[4]	138,034	[4]
Affiliated Entity [Member]
Accounts receivable, net	64,500		47,800
Other current assets	200		100
Accounts and natural gas imbalance payables	100		2,300
Accrued liabilities	$ 0		$ 100

[1] Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $64.5 million and $47.8 million as of December 31, 2014 and 2013, respectively.

[2] Other current assets includes natural gas imbalance receivables from affiliates of $0.2 million and $0.1 million as of December 31, 2014 and 2013, respectively.

[3] Accounts and natural gas imbalance payables includes amounts payable to affiliates of $0.1 million and $2.3 million as of December 31, 2014 and 2013, respectively.

[4] Accrued liabilities includes amounts payable to affiliates of zero and $0.1 million as of December 31, 2014 and 2013, respectively.