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 Stock		Oct. 31, 2008 Series F Preferred Stock
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
Number of years of long dated treasuries	30 years
Treasury rate of agreement					5.2175%
Mark-to-Market Gain (Loss) on Interest Rate Protection Agreements	(52)	328
Settlement payments of mark-to-market gains or losses	774	1,169
Amortization to be reclassified from OCI into income	1,358
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.