Accumulated Other Comprehensive Income (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Amount Reclassified from AOCI
Realized gains on sale of securities	$ 31	$ 27
Interest income on taxable securities	2,462	3,097
Income before income taxes	3,035	3,026
Income tax expense	(855)	(951)
Net income	2,180	2,075
Amount Reclassified from AOCI
Amount Reclassified from AOCI
Net income	(15)	(25)
Unrealized gains on available-for-sale securities and I/O strips | Amount Reclassified from AOCI
Amount Reclassified from AOCI
Realized gains on sale of securities	31	27
Income tax expense	(13)	(11)
Net income	18	16
Unamortized Unrealized Gain on Available-for-Sale Securities Reclassified to Held-to-Maturity | Amount Reclassified from AOCI
Amount Reclassified from AOCI
Interest income on taxable securities	14
Income tax expense	(6)
Net income	8
Amortization of defined benefit pension plan items | Amount Reclassified from AOCI
Amount Reclassified from AOCI
Prior service cost		(7)
Actuarial losses	(71)	(63)
Income before income taxes	(71)	(70)
Income tax expense	30	29
Net income	$ (41)	$ (41)