Investment Securities (Details 2) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 securities	Jun. 30, 2012
Investment Securities
Number of individual securities that were in a continuous unrealized loss position for less than twelve months	182
Number of individual securities that were in a continuous unrealized loss position for greater than twelve months	13
Available for Sale, Amortized Cost
Due in one year or less	$ 6,180
Due after one year to five years	41,234
Due after five years to ten years	87,544
Due after ten years	165,316
Total amortized cost	300,274
Available for Sale, Fair Value
Due in one year or less	6,197
Due after one year to five years	41,746
Due after five years to ten years	85,721
Due after ten years	165,565
Total fair value	299,229
Gross proceeds from sales of securities	$ 42,910	$ 18,014