Summary of Quarterly Results (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																								12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary Of Quarterly Results
Interest income	$ 6,762		$ 6,833		$ 6,618		$ 6,405		$ 6,728		$ 6,772		$ 6,692		$ 6,624		$ 6,937		$ 6,933		$ 6,679		$ 6,695
Interest expense	988		1,099		1,168		1,231		1,363		1,350		1,375		1,423		1,643		1,770		1,799		1,879		4,486	5,511	7,091
Net interest income	5,774		5,734		5,450		5,174		5,365		5,422		5,317		5,201		5,294		5,163		4,880		4,816		22,132	21,305	20,153
Provision for loan losses	140		140		140		140		0		3,340		352		323		460		0		165		160		560	4,015	785
Noninterest income	1,524		1,481		1,369		1,320		1,274		1,411		1,523		1,415		1,559		1,444		2,323		1,242		5,694	5,623	6,568
Net income	$ 1,805		$ 1,782		$ 1,403		$ 1,450		$ 1,561		$ 13		$ 1,561		$ 1,609		$ 1,685		$ 1,226		$ 1,918		$ 1,180		$ 6,440	$ 4,744	$ 6,009
Basic earnings per share	$ 1.10	[1]	$ 1.08	[1]	$ 0.85	[1]	$ 0.87	[1]	$ 0.95	[1]	$ 0.01	[1]	$ 0.95	[1]	$ 0.97	[1]	$ 1.01	[1]	$ 0.74	[1]	$ 1.15	[1]	$ 0.7	[1]	$ 3.90	$ 2.87	$ 3.61
Diluted earnings per share	$ 1.10	[1]	$ 1.08	[1]	$ 0.85	[1]	$ 0.87	[1]	$ 0.95	[1]	$ 0.01	[1]	$ 0.95	[1]	$ 0.97	[1]	$ 1.01	[1]	$ 0.74	[1]	$ 1.15	[1]	$ 0.7	[1]	$ 3.90	$ 2.87	$ 3.61

[1] Basic and diluted earnings per share may not foot to the total for the year ended December 31 due to rounding.