Restricted Share Grants - Additional Information (Detail) (USD $)	0 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended	0 Months Ended	1 Months Ended
	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Restricted Shares [Member]	Jun. 30, 2014 Restricted Shares [Member]	Feb. 28, 2013 2007 Stock Option Plan [Member] Restricted Shares [Member]	May 28, 2013 2007 Stock Option Plan [Member] Restricted Shares [Member]	May 21, 2013 2007 Stock Option Plan [Member] Restricted Shares [Member]	Jan. 31, 2013 2007 Stock Option Plan [Member] Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance								1,000,000	600,000
Increase in shares issuable under the Trust's 2007 Stock Option Plan by shareholders									500,000
Initial Restricted Shares issued						100,000	500,000
Non-cash compensation expense		$ 1,331,000	$ 211,000	$ 917,000	$ 1,331,000
Restricted Shares forfeited	7,500
Unrecognized compensation cost			$ 6,866,000
Unrecognized compensation cost, forfeiture	592,500
Reissuance of forfeited restricted shares	7,500