Allowance for loan losses and credit quality Impaired Loans by Class (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
With an allowance recorded, Recorded Investment	$ 3,293	[1]	$ 2,879	[2]
With an allowance recorded, Principal Balance	3,307	[1]	2,921	[2]
Related Allowance	337		120
With no allowance recorded, Recorded Investment	2,204	[1]	1,523	[2]
With no allowance recorded, Principal Balance	2,511	[1]	1,751	[2]
Total, Recorded Investment	5,497	[1]	4,402	[2]
Total, Principal Balance	5,818	[1]	4,672	[2]
Total, Average Recorded Investment	5,755		3,140
Total, Interest Income Recognized	274		127
Government Guarantees on Impaired Loans	(669)		(770)
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
With an allowance recorded, Recorded Investment	437		354
With an allowance recorded, Principal Balance	451		360
Related Allowance	46		49
With no allowance recorded, Recorded Investment	384		349
With no allowance recorded, Principal Balance	612		491
Total, Recorded Investment	821		703
Total, Principal Balance	1,063		851
Total, Average Recorded Investment	871		529
Total, Interest Income Recognized	19		9
Construction Real Estate [Member]
Financing Receivable, Impaired [Line Items]
With an allowance recorded, Recorded Investment	322		145
With an allowance recorded, Principal Balance	322		150
Related Allowance	13		18
With no allowance recorded, Recorded Investment	26
With no allowance recorded, Principal Balance	48
Total, Recorded Investment	348		145
Total, Principal Balance	370		150
Total, Average Recorded Investment	267		46
Total, Interest Income Recognized	9		1
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
With an allowance recorded, Recorded Investment	2,534	[1]	2,380	[2]
With an allowance recorded, Principal Balance	2,534	[1]	2,411	[2]
Related Allowance	278		53
With no allowance recorded, Recorded Investment	1,685	[1]	1,047	[2]
With no allowance recorded, Principal Balance	1,742	[1]	1,133	[2]
Total, Recorded Investment	4,219	[1]	3,427	[2]
Total, Principal Balance	4,276	[1]	3,544	[2]
Total, Average Recorded Investment	4,499		2,514
Total, Interest Income Recognized	239		115
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance	0		0
With no allowance recorded, Recorded Investment	109		127
With no allowance recorded, Principal Balance	109		127
Total, Recorded Investment	109		127
Total, Principal Balance	109		127
Total, Average Recorded Investment	118		51
Total, Interest Income Recognized	$ 7		$ 2

[1] Does not reflect government guaranties on impaired loans as of December 31, 2013 totaling $669 thousand.

[2] Does not reflect government guaranties on impaired loans as of December 31, 2012 totaling $770 thousand.