Fair value measurements (Details 4) (Fair Value, Inputs, Level 3, USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Fair value measurements
Fair value	$ 2,855	$ 4,416
Weighted average discount rate		4.50%
Residential loan | Fair value of property or collateral
Fair value measurements
Fair value	2,519	2,361
Appraised value, selling cost	7.00%	7.00%
Appraised value, weighted average rate (as a percent)	85.00%	87.00%
Residential loan | Fair value of property or collateral | Minimum
Fair value measurements
Appraised value (as a percent)	61.00%	44.00%
Residential loan | Fair value of property or collateral | Maximum
Fair value measurements
Appraised value (as a percent)	96.00%	96.00%
Home equity line of credit | Fair value of property or collateral
Fair value measurements
Fair value		170
Appraised value, selling cost		7.00%
Appraised value, weighted average rate (as a percent)		50.00%
Home equity line of credit | Fair value of property or collateral | Minimum
Fair value measurements
Appraised value (as a percent)		45.00%
Home equity line of credit | Fair value of property or collateral | Maximum
Fair value measurements
Appraised value (as a percent)		50.00%
Commercial loans | Fair value of property or collateral
Fair value measurements
Fair value	336	217
Fair value, weighted average rate (as a percent)	25.00%	19.00%
Commercial loan 2 | Fair value of property or collateral | Minimum
Fair value measurements
Fair value of business assets (as a percent)	19.00%
Commercial loan 2 | Fair value of property or collateral | Maximum
Fair value measurements
Fair value of business assets (as a percent)	49.00%
Commercial loan 2 | Discounted Cash Flow [Member]
Fair value measurements
Fair value		$ 1,668
Fair value, weighted average rate (as a percent)		58.00%