Partners' Capital (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Dividend Distributions
Total Distribution	$ 4,798	$ 4,947	$ 9,560	$ 9,874
Series F Preferred Unit [Member]
Dividend Distributions
Distribution per Unit			$ 2,811
Total Distribution			1,405
Series G Preferred Unit [Member]
Dividend Distributions
Distribution per Unit			$ 3,618
Total Distribution			905
Series J Preferred Unit [Member]
Dividend Distributions
Distribution per Unit			$ 9,063
Total Distribution			5,438
Series K Preferred Unit [Member]
Dividend Distributions
Distribution per Unit			$ 9,063
Total Distribution			$ 1,812