Derivatives and Hedging Activities (Details 2) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Credit Risk Related Contingent Features
Aggregate fair value of derivatives with credit-risk-related contingent features, net liability position	$ 1,600,000
Collateral posted	2,400,000
Number of derivative counterparties that the company has an agreement with that contain a provision where if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations	1
Interest expense
Cash Flow Hedges of Interest Rate Risk
Estimated amount of interest rate cash flow hedge gain (loss) to be reclassified in the next 12 months	(703,000)
Cash flow hedges
Cash Flow Hedges of Interest Rate Risk
Hedge ineffectiveness recognized	0	0
Amount of gain/(loss) reclassified from AOCI into earnings - effective portion	(175,000)	(166,000)
Cash flow hedges | Net interest income
Cash Flow Hedges of Interest Rate Risk
Amount of gain/(loss) reclassified from AOCI into earnings - effective portion	(175,000)	(166,000)
Cash flow hedges | Interest rate swaps
Cash Flow Hedges of Interest Rate Risk
Number of derivative instruments held	2
Notional amount	17,500,000
Pre-tax gain/(loss) recorded in AOCI due to the effective portion of changes in fair value	$ (7,000)	$ (73,000)