Derivative Instruments and Fair Value Measurements (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Notional Amount, Outstanding (in dollars)	$ 166,300,000	$ 203,052,038
Interest Rate Swap [Member]
Notional Amount, Outstanding (in dollars)	0	36,752,038
Fixed Rate	5.225%	5.225%
Maturity	08/2012	08/2012
Interest Rate Swap 1 [Member]
Notional Amount, Outstanding (in dollars)	81,500,000	81,500,000
Fixed Rate	3.895%	3.895%
Maturity	01/2013	01/2013
Interest Rate Swap 2 [Member]
Notional Amount, Outstanding (in dollars)	$ 84,800,000	$ 84,800,000
Fixed Rate	3.90%	3.90%
Maturity	09/2013	09/2013