Fair Value of Financial Instruments - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013
Business Acquisition, Pro Forma Information [Line Items]
OP units tendered for redemption			591,474
Common stock issued in connection with redemption shares			531,768
Cash paid for redemption			$ 1,900,000
Gains / (loss) as a result of the excess of the fair value of the guarantee over the fair value of the consideration	(16,000)	174,000
Increase in additional paid in capital and common stock, par value	279,000	1,400,000	279,000
Additional gains due to changes in fair value of financial instruments and gain on OP unit redemption	$ 246,000	$ 288,000