Derivatives (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								1 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 2011 Interest Rate Swap [Member]	Dec. 31, 2011 2011 Interest Rate Swap [Member]	Mar. 31, 2011 2011 Interest Rate Swap [Member]	Mar. 31, 2012 2006 Interest Rate Swap [Member]	Dec. 31, 2011 2006 Interest Rate Swap [Member]	Mar. 31, 2011 2006 Interest Rate Swap [Member]	Dec. 31, 2011 2009 Interest Rate Swap [Member]	Mar. 31, 2012 2009 Interest Rate Swap [Member]	Mar. 31, 2011 2009 Interest Rate Swap [Member]
Derivative [Line Items]
Notional amount of interest rate derivatives			$ 93,500	$ 93,500	$ 0	$ 0	$ 0	$ 115,000	$ 0	$ 0	$ 115,000
Fixed rate payments, interest rate			5.50%			7.125%				5.50%
Variable rate payment rate			1.75%			1.75%				1.75%
Fair value of collateral pledged to secure interest rate contracts	14,668
Incremental interest expense paid to interest rate swap counterparties	749	1,458
Purchase of underlying basis of trust preferred capital securities									$ 21,500