Net Income/(Loss) Per Limited Partner Unit (Calculation Of Net Loss Per Limited Partner Unit) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended					6 Months Ended				12 Months Ended
	Jun. 30, 2013		Mar. 31, 2013	Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Schedule Of Earnings Per Partner Unit [Line Items]
Net income	$ 63,614			$ 130,700		$ 55,440		$ 122,474
Net income (loss) attributable to predecessor operations				(31,575)				(30,584)
Distributions to unitholders						(70,752)
Amortization of preferred unit discount	(3,868)			(3,713)		(7,697)		(7,389)
Net income (loss) available to other unitholders	53,256			91,912		34,763		77,501
General partner's interest in net income (loss)	36			(703)		770		2,455
Limited partners' interest in net income (loss)	53,220			92,615		33,993		75,046
Common unitholders' interest in net income (loss)	53,220			77,478		33,993		62,454
Subordinated unitholders' interest in net income (loss)				15,137				12,592
Weighted average preferred units outstanding	16,666,667			16,666,667		16,666,667		16,666,667
Limited Partners - Public And Affiliated Common Units [Member]
Schedule Of Earnings Per Partner Unit [Line Items]
Unitholders' (basic) (in dollars per unit)	$ 0.89			$ 2.15		$ 0.58		$ 1.92
Unitholders' (diluted) (in dollars per unit)	$ 0.77			$ 1.67		$ 0.58		$ 1.60
Common units (basic) (in units)	59,556,000	[1]		36,114,000	[1]	58,455,000	[1]	32,486,000	[1]
Common units (diluted) (in units)	82,356,000	[1]		52,780,000	[1]	58,455,000	[1]	49,153,000	[1]
Limited Partners-Affiliated - Subordinated [Member]
Schedule Of Earnings Per Partner Unit [Line Items]
Unitholders' (basic) (in dollars per unit)				$ 2.12				$ 1.76
Unitholders' (diluted) (in dollars per unit)				$ 1.65	[1]			$ 1.50	[1]
Subordinated units (basic and diluted) (in units)				7,146,000	[1]			7,146,000	[1]
Class B Units [Member]
Schedule Of Earnings Per Partner Unit [Line Items]
Distributions to unitholders	(2,990)		(2,990)			(5,980)				(2,990)
Weighted average Class B units outstanding	6,133,558			0		4,961,597		0
Class C Convertible Preferred [Member]
Schedule Of Earnings Per Partner Unit [Line Items]
Distributions to unitholders	$ (3,500)			$ (3,500)		$ (7,000)		$ (7,000)

[1] For the three and six months ended June 30, 2013 and 2012, we had weighted average preferred units outstanding of 16,666,667. For the three months ended June 30, 2013 and 2012, we had 6,133,558 and zero Class B units outstanding, respectively. For the six months ended June 30, 2013 and 2012, we had 4,961,597 and zero Class B units outstanding, respectively. The preferred and Class B units are contingently convertible into common units and could potentially dilute earnings per unit in the future.