Common Shares - Sales of Common Shares (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2013
Series B One Preferred Stock [Member]
Class of Stock [Line Items]
Number of right share offered per basic subscription	1
Number of basic subscribed shares considered for base of right share offer	3.5
Common Shares of Beneficial Interest [Member]
Class of Stock [Line Items]
Number of right share offered per basic subscription	1
Number of basic subscribed shares considered for base of right share offer	3.5