Stock Offering Stock Offering (Textual) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Offering [Abstract]
Sale of common stock shares		$ 125,000,000
Number of shares sold under sales agreement	572,510
Proceeds from issuance of common stock under secondary security offering		$ 0	$ 10,283,000	$ 0