MEMBERS' EQUITY Table 1 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Changes in Members' Equity [Roll Forward]
Balance as of December 31, 2014	$ 310,836us-gaap_MembersEquity
Net income	26,805us-gaap_NetIncomeLoss	13,646us-gaap_NetIncomeLoss
Distributions to unitholders	(23,403)us-gaap_PaymentsOfDividendsCommonStock	(23,249)us-gaap_PaymentsOfDividendsCommonStock
Other comprehensive income (loss)	(3,265)
Unit-based compensation	126
Other	16us-gaap_StockholdersEquityOther
Balance as of March 31, 2015	$ 311,115us-gaap_MembersEquity

This element represents the amount of recognized equity-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Alternate captions include the words "stock-based compensation".

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Amount of ownership interest in limited liability company (LLC), attributable to the parent entity.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

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