Condensed Consolidated Statements Of Partners' Capital (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Statement of Partners' Capital [Abstract]
Partners' capital, January 1, units	81,202,752	71,965,000
Partners' capital, January 1, value	$ 916,495	$ 792,638
Net income	68,222	69,382
Cash distributions	(122,097)	(104,008)
Issuance of common units for cash, net, units	5,750,000	5,750,000
Issuance of common units for cash, net, value	263,597	169,421
Conversion of waiver units, units	1,738,233	3,476,000
Conversion of waiver units, value	0	0
Other, units	0	12,000
Other, value	0	500
Partners' capital, September 30, units	88,690,985	81,203,000
Partners' capital, September 30, value	$ 1,126,217	$ 927,933