Derivative Financial Instruments (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Derivatives not designated as hedging instruments, fair value
Interest rate swaps - assets	3,128,000	3,434,000
Interest rate swaps - liabilities	3,128,000	3,434,000
Other assets
Derivatives not designated as hedging instruments, fair value
Description of Location of Interest Rate Derivative Instruments Not Designated as Hedging Instruments on Balance Sheet	Other assets	Other assets
Other liabilities
Derivatives not designated as hedging instruments, fair value
Description of Location of Interest Rate Derivative Instruments Not Designated as Hedging Instruments on Balance Sheet	Other liabilities	Other liabilities