Derivatives - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Series F Preferred Units [Member]		Oct. 31, 2008 Series F Preferred Units [Member]
Derivative [Line Items]
Minimum fixed coupon rate of preferred stock			2.375%
Number of years of U.S. treasury rate one			30 years
Number of years of U.S. treasury rate two			10 years
LIBOR rate			3-month LIBOR
New coupon rate of preferred stock			6.065%
Notional value of interest rate swap agreement			$ 50,000	[1]	$ 50,000
Treasury rate of agreement					5.2175%
Mark-to-Market Loss on Interest Rate Protection Agreement	52	328
Settlement payments of mark to market gains or losses	774	1,169
Amortization to be reclassified from OCI into income	1,358
Number of years of long dated treasuries	30 years
Outstanding settlement payment due on the agreement	$ 0	$ 305

[1] Fair value excludes quarterly settlement payment due on Series F Agreement. As of December 31, 2012, the outstanding payable was $305.