Common Stock (Details Textual) (USD $)	1 Months Ended		3 Months Ended
	Mar. 31, 2013	Jan. 31, 2013	Mar. 31, 2013	Mar. 31, 2012	Jan. 18, 2013
Stock Issued During Period, Shares, New Issues		1,725,000
Sale Of Stock, Price Per Share (in dollars per share)					$ 27.25
Proceeds From Issuance Of Common Stock (in dollars)	$ 45,000,000		$ 44,810,620	$ 35,042,235
Over Allotment Option [Member]
Sale Of Stock, Number Of Shares Issued In Transaction			225,000