Partners' Capital - Summary of Distributions (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Class of Stock [Line Items]
Total Preferred Unit Distribution	$ 2,481		$ 14,400		$ 20,751
General Partner/Limited Partner Units
Class of Stock [Line Items]
Total General/Limited Partner Unit Distribution	47,263		38,862
Series F Preferred Units
Class of Stock [Line Items]
Total Preferred Unit Distribution	566	[1]	2,896		2,728
Series G Preferred Units
Class of Stock [Line Items]
Total Preferred Unit Distribution	453	[1]	1,809		1,809
Series J Preferred Units
Class of Stock [Line Items]
Total Preferred Unit Distribution			2,034	[1]	10,785	[1]
Series K Preferred Units
Class of Stock [Line Items]
Total Preferred Unit Distribution			$ 1,994	[1]	$ 3,625

[1] See the "Preferred Contributions" section for the redemptions and discussion of pro-rated dividends for all series of preferred stock occurring during the years ended December 31, 2014, 2013 and 2012.