5. Securities (Summary of Volume of State and Political Subdivision Securities Held in Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Available for sale securities, Amortized Cost	$ 290,603	$ 283,033	$ 273,684
Available for sale securities, Unrealized Gains	4,809	9,906	8,855
Available for sale securities, Unrealized Losses	4,154	947	1,000
Available for sale securities, Estimated Fair Value	291,258	291,992	281,539
West Virginia [Member]
Available for sale securities, Amortized Cost	14,286
Available for sale securities, Unrealized Gains	97
Available for sale securities, Unrealized Losses	267
Available for sale securities, Estimated Fair Value	14,116
Illinois [Member]
Available for sale securities, Amortized Cost	10,435
Available for sale securities, Unrealized Gains	59
Available for sale securities, Unrealized Losses	535
Available for sale securities, Estimated Fair Value	9,959
California [Member]
Available for sale securities, Amortized Cost	8,102
Available for sale securities, Unrealized Gains	107
Available for sale securities, Unrealized Losses	241
Available for sale securities, Estimated Fair Value	7,968
Texas [Member]
Available for sale securities, Amortized Cost	7,155
Available for sale securities, Unrealized Gains	234
Available for sale securities, Unrealized Losses	178
Available for sale securities, Estimated Fair Value	7,211
Washington [Member]
Available for sale securities, Amortized Cost	4,409
Available for sale securities, Unrealized Gains	110
Available for sale securities, Unrealized Losses	80
Available for sale securities, Estimated Fair Value	$ 4,439