Securities, Temporarily impaired securities (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Temporarily Impaired Securities [Abstract]
Less Than 12 Months, Fair Value	$ 52,096	$ 14,673
Less Than 12 Months, Unrealized Loss	877	136
12 Months or More, Fair Value	2,648	1,123
12 Months or More, Unrealized Loss	195	188
Number of temporarily impaired securities	62
Fair Value of temporarily impaired securities	54,744
Unrealized loss on securities	1,072
Number of securities that were temporarily impaired in a continuous loss position for twelve months or more	5
Securities In Unrealized Loss Positions 12 Months Or Longer Fair Value	2,648
Securities In Unrealized Loss Positions 12 Months Or Longer Unrealized Loss	196
U.S. Government agencies and corporations [Member]
Temporarily Impaired Securities [Abstract]
Less Than 12 Months, Fair Value	41,282	6,230
Less Than 12 Months, Unrealized Loss	709	20
12 Months or More, Fair Value	0	0
12 Months or More, Unrealized Loss	0	0
States and political subdivisions [Member]
Temporarily Impaired Securities [Abstract]
Less Than 12 Months, Fair Value	10,814	3,527
Less Than 12 Months, Unrealized Loss	168	19
12 Months or More, Fair Value	536	981
12 Months or More, Unrealized Loss	3	26
Corporate debt securities [Member]
Temporarily Impaired Securities [Abstract]
Less Than 12 Months, Fair Value	0	4,916
Less Than 12 Months, Unrealized Loss	0	97
12 Months or More, Fair Value	1,979	0
12 Months or More, Unrealized Loss	21	0
Other [Member]
Temporarily Impaired Securities [Abstract]
Less Than 12 Months, Fair Value	0	0
Less Than 12 Months, Unrealized Loss	0	0
12 Months or More, Fair Value	133	142
12 Months or More, Unrealized Loss	$ 171	$ 162