Income (Loss) Per Common Share (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income (Loss) Per Common Share
Net income (loss)	$ (87,656,965)	$ (3,846,124)	$ 3,910,819	$ (4,399,085)	$ (4,999,457)	$ 526,600	$ (2,826,563)	$ (8,545,962)	$ (91,991,355)	$ (15,845,382)	$ (30,844,897)
Weighted-average number of shares of Common Stock - basic	44,269,388	44,208,471	44,134,330	43,976,950	43,904,661	45,121,172	45,188,542	44,939,828	44,147,787	44,788,551	39,397,486
Loss per share - basic (in dollars per share)	$ (1.98)	$ (0.09)	$ 0.09	$ (0.10)	$ (0.11)	$ 0.01	$ (0.06)	$ (0.19)	$ (2.08)	$ (0.35)	$ (0.78)
Weighted-average number of shares of Common Stock - diluted	44,269,388	44,208,471	44,992,883	43,976,950	43,904,661	45,166,566	45,188,542	44,939,828	44,147,787	44,788,551	39,397,486
Loss per share - diluted (in dollars per share)	$ (1.98)	$ (0.09)	$ 0.09	$ (0.10)	$ (0.11)	$ 0.01	$ (0.06)	$ (0.19)	$ (2.08)	$ (0.35)	$ (0.78)
Potential dilutive securities have not been considered, their effects would be antidilutive (in shares)									560,469	82,634	95,967