Basis of Presentation (Details Textuals) (USD $) Share data in Millions, unless otherwise specified	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Basis of Presentation (Textuals) [Abstract]
Weighted average common shares - basic restricted stock		3.6	3.4	3.7	3.5
Distribution on Vanguard common units			$ 1,800,000		$ 5,300,000
Proceeds from sale of short-term investments	83,545,000			83,545,000	0
Loss on sale of Vanguard securities				$ 3,100,000