Bank segment - Troubled debt restructuring that subsequently defaulted (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) contract	Sep. 30, 2014 USD ($) contract	Sep. 30, 2015 USD ($) contract	Sep. 30, 2014 USD ($) contract
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	1	0	1	1
Recorded investment	$ 7	$ 0	$ 7	$ 390
Home equity line of credit
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	1		1
Recorded investment	$ 7		$ 7
Residential 1-4 family
Financing Receivable, Modifications [Line Items]
Number of contracts | contract		0		1
Recorded investment		$ 0		$ 390