Condensed Consolidated Statements Of Partners' Capital - USD ($) shares in Thousands, $ in Thousands	Total	Partners’ Capital	Noncontrolling Interest	Common Units Partners’ Capital
Partners' capital, beginning of period at Dec. 31, 2013	$ 1,097,737	$ 1,097,737	$ 0
Partners' capital, beginning of period (in units) at Dec. 31, 2013				88,691
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	80,036	80,036	0
Cash distributions to partners, net	(146,350)	(146,350)
Cash distributions to noncontrolling interests	0		0
Issuance of common units for cash, net (in units)				4,600
Issuance of common units for cash, net	225,610	225,610	0
Partners' capital, end of period at Sep. 30, 2014	1,257,033	1,257,033	0
Partners' capital, end of period (in units) at Sep. 30, 2014				93,291
Partners' capital, beginning of period at Dec. 31, 2014	1,229,203	1,229,203	0
Partners' capital, beginning of period (in units) at Dec. 31, 2014				95,029
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	395,289	395,094	195
Noncontrolling interest from acquisition	(6,471)		(6,471)
Cash distributions to partners, net	(186,026)	(186,026)
Cash distributions to noncontrolling interests	(560)		(560)
Issuance of common units for cash, net (in units)				14,950
Issuance of common units for cash, net	633,759	633,759	0
Partners' capital, end of period at Sep. 30, 2015	$ 2,065,194	$ 2,072,030	$ (6,836)
Partners' capital, end of period (in units) at Sep. 30, 2015				109,979