Financing Activity - Mortgage Loan Activity (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	1 Months Ended			1 Months Ended	3 Months Ended
	Mar. 31, 2013	Feb. 28, 2013 Lycoming Mall [Member]	Mar. 31, 2010 Lycoming Mall [Member]	Oct. 31, 2009 Lycoming Mall [Member]	Feb. 28, 2013 Mortgage Loan February [Member] Lycoming Mall [Member]	Mar. 31, 2013 Mortgage Loan February [Member] Lycoming Mall [Member]
Mortgage Loan Activity [Line Items]
Mortagage amount increased	$ 7.9
Initial amount of mortgage loan		28.0
Stated Interest Rate					LIBOR plus 2.75%	LIBOR plus 2.75%
Additional amount drawn		2.1	2.5	5.0
Total mortgage amount		35.5
Unamortized balance of mortgage loan		$ 33.4