Consolidated Statement Of Changes In Partners' Capital (Unaudited) (USD $) In Thousands	Limited Partners-Affiliated - Common [Member] Limited Partner [Member] Limited Partners-Public Common [Member]	Limited Partners-Affiliated - Common [Member] Limited Partner [Member]	Class C Convertible Preferred [Member]	General Partner [Member]	Limited Partner [Member] Limited Partners-Public Common [Member]	Limited Partner [Member] Limited Partners-Affiliated - Common [Member]	Limited Partner [Member] Limited Partners-Affiliated - Subordinated [Member]	Total
Balances at Dec. 31, 2011			$ 358,138					$ 414,841
Amortization of discount on increasing rate distributions			11,140					11,140
Balances at Jun. 30, 2012
Balances at Dec. 31, 2011			358,138	546	241,306	(113,414)	(71,735)	414,841
Contributions from the Predecessor						4,985	17,239	22,224
Proceeds from unit offering	(113,325)	113,325			161,958			161,958
Units issued to the General Partner				115				115
Recognition of unit-based awards					2,125			2,125
Reduction in units to cover individuals' tax withholding					(21)			(21)
Distributions to unitholders			(10,500)	(60)	(55,100)		(10,362)	(76,022)
Noncash distribution to preferred unitholders			(11,140)					(11,140)
Management incentive fee earned				(6,121)				(6,121)
Net income			21,640	6,134	21,635	(4,896)	2,370	46,883
Balances at Sep. 30, 2012			$ 369,278	$ 614	$ 258,578		$ (62,488)	$ 565,982