Loans, Credit Quality Indicator (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2013	Dec. 31, 2014
Financing Receivable by credit exposure [Abstract]
Total	$ 192,009,000		$ 193,935,000
Minimum [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of dollar volume of commercial loan portfolio to be reviewed (in hundredths)	55.00%	60.00%
Amount over which all new loans to be reviewed, minimum	1,000,000
Amount over which all relationships to be reviewed, minimum	1,000,000
Amount which is 30 days past due to be reviewed for all aggregate loan relationships	750,000
Construction [Member]
Financing Receivable by credit exposure [Abstract]
Total	6,036,000		6,353,000
Mortgages [Member]
Financing Receivable by credit exposure [Abstract]
Total	123,111,000		122,858,000
Home Equity [Member]
Financing Receivable by credit exposure [Abstract]
Total	60,727,000		62,580,000
Commercial [Member]
Financing Receivable by credit exposure [Abstract]
Total	192,701,000		190,945,000
Agricultural [Member]
Financing Receivable by credit exposure [Abstract]
Total	25,691,000		24,639,000
Consumer [Member]
Financing Receivable by credit exposure [Abstract]
Total	8,171,000		8,497,000
Other Commercial Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	52,606,000		47,451,000
Other Agricultural Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	10,780,000		11,065,000
State and Political Subdivision Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	85,356,000		79,717,000
Pass [Member]
Financing Receivable by credit exposure [Abstract]
Total	343,244,000		324,932,000
Pass [Member] | Construction [Member]
Financing Receivable by credit exposure [Abstract]
Total	6,036,000		6,353,000
Pass [Member] | Commercial [Member]
Financing Receivable by credit exposure [Abstract]
Total	175,890,000		169,383,000
Pass [Member] | Agricultural [Member]
Financing Receivable by credit exposure [Abstract]
Total	20,695,000		19,575,000
Pass [Member] | Other Commercial Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	46,267,000		40,683,000
Pass [Member] | Other Agricultural Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	9,000,000		9,221,000
Pass [Member] | State and Political Subdivision Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	85,356,000		79,717,000
Special Mention [Member]
Financing Receivable by credit exposure [Abstract]
Total	13,057,000		17,482,000
Special Mention [Member] | Construction [Member]
Financing Receivable by credit exposure [Abstract]
Total	0		0
Special Mention [Member] | Commercial [Member]
Financing Receivable by credit exposure [Abstract]
Total	4,912,000		8,948,000
Special Mention [Member] | Agricultural [Member]
Financing Receivable by credit exposure [Abstract]
Total	3,361,000		3,394,000
Special Mention [Member] | Other Commercial Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	4,109,000		4,413,000
Special Mention [Member] | Other Agricultural Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	675,000		727,000
Special Mention [Member] | State and Political Subdivision Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	0		0
Substandard [Member]
Financing Receivable by credit exposure [Abstract]
Total	16,677,000		17,756,000
Substandard [Member] | Construction [Member]
Financing Receivable by credit exposure [Abstract]
Total	0		0
Substandard [Member] | Commercial [Member]
Financing Receivable by credit exposure [Abstract]
Total	11,855,000		12,614,000
Substandard [Member] | Agricultural [Member]
Financing Receivable by credit exposure [Abstract]
Total	1,635,000		1,670,000
Substandard [Member] | Other Commercial Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	2,082,000		2,355,000
Substandard [Member] | Other Agricultural Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	1,105,000		1,117,000
Substandard [Member] | State and Political Subdivision Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	0		0
Doubtful [Member]
Financing Receivable by credit exposure [Abstract]
Total	192,000		0
Doubtful [Member] | Construction [Member]
Financing Receivable by credit exposure [Abstract]
Total	0		0
Doubtful [Member] | Commercial [Member]
Financing Receivable by credit exposure [Abstract]
Total	44,000		0
Doubtful [Member] | Agricultural [Member]
Financing Receivable by credit exposure [Abstract]
Total	0		0
Doubtful [Member] | Other Commercial Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	148,000		0
Doubtful [Member] | Other Agricultural Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	0		0
Doubtful [Member] | State and Political Subdivision Loans [Member]
Financing Receivable by credit exposure [Abstract]
Total	0		0
Internally Assigned Grade [Member]
Financing Receivable by credit exposure [Abstract]
Total	373,170,000		360,170,000
Performing [Member]
Financing Receivable by credit exposure [Abstract]
Total	190,661,000		192,708,000
Performing [Member] | Mortgages [Member]
Financing Receivable by credit exposure [Abstract]
Total	122,090,000		121,968,000
Performing [Member] | Home Equity [Member]
Financing Receivable by credit exposure [Abstract]
Total	60,458,000		62,296,000
Performing [Member] | Consumer [Member]
Financing Receivable by credit exposure [Abstract]
Total	8,113,000		8,444,000
Nonperforming [Member]
Financing Receivable by credit exposure [Abstract]
Total	1,348,000		1,227,000
Nonperforming [Member] | Mortgages [Member]
Financing Receivable by credit exposure [Abstract]
Total	1,021,000		890,000
Nonperforming [Member] | Home Equity [Member]
Financing Receivable by credit exposure [Abstract]
Total	269,000		284,000
Nonperforming [Member] | Consumer [Member]
Financing Receivable by credit exposure [Abstract]
Total	$ 58,000		$ 53,000