Securities (Details 3) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Held-to-maturity Securities [Abstract]
Amortized Cost, Held to Maturity, Due within one year	$ 9,446
Amortized Cost, Held to Maturity, Due after one year through five years	32,811
Amortized Cost, Held to Maturity, Due after five years through ten years	167,412
Amortized Cost, Held to Maturity, Due after ten years	138,671
Amortized Cost, Held to Maturity	348,340	317,766
Fair Value, Held to Maturity, Due within one year	9,509
Fair Value, Held to Maturity, Due after one year through five years	33,950
Fair Value, Held to Maturity, Due after five years through ten years	163,309
Fair Value, Held to Maturity, Due after ten years	140,387
Fair Value, Held to Maturity	347,155	334,475
Available for Sale Securities [Abstract]
Amortized Cost, Available for Sale, Due after five years through ten years	6,157
Amortized Cost, Available for Sale, Due after ten years	27,711
Amortized Cost, Available for Sale	410,535	357,633
Fair Value, Available for Sale, Due after five years through ten years	6,120
Fair Value, Available for Sale, Due after ten years	15,960
Fair Value, Available for Sale	398,190	356,311
Other debt securities [Member]
Available for Sale Securities [Abstract]
Amortized Cost, Available for Sale	20,834	22,079
Fair Value, Available for Sale	21,280	22,930
Other equity securities [Member]
Available for Sale Securities [Abstract]
Amortized Cost, Available for Sale	2,775	2,355
Fair Value, Available for Sale	3,741	3,068
Government agency mortgage backed securities [Member] | Residential mortgage backed securities [Member]
Available for Sale Securities [Abstract]
Amortized Cost, Available for Sale	173,460	139,699
Fair Value, Available for Sale	171,902	144,817
Government agency mortgage backed securities [Member] | Commercial mortgage backed securities [Member]
Available for Sale Securities [Abstract]
Amortized Cost, Available for Sale	41,621	41,981
Fair Value, Available for Sale	42,753	45,058
Government agency collateralized mortgage obligations [Member] | Residential mortgage backed securities [Member]
Available for Sale Securities [Abstract]
Amortized Cost, Available for Sale	132,927	115,647
Fair Value, Available for Sale	131,356	117,521
Government agency collateralized mortgage obligations [Member] | Commercial mortgage backed securities [Member]
Available for Sale Securities [Abstract]
Amortized Cost, Available for Sale	5,050	5,091
Fair Value, Available for Sale	$ 5,078	$ 5,407