Other Real Estate Owned - Changes in OREO (Details) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($) property	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Foreclosed Property [Roll Forward]
Beginning balance	$ 3,536	$ 7,435	$ 7,435
Net proceeds from sales	(2,130)	(1,127)	(5,465)
Net gains (losses) on sales	404	7	678
Transfers in	44	821	859
Cash additions	35		290
Impairment charge	(209)	(143)	(261)
Ending balance	1,680		3,536
Loans
Foreclosed Property [Roll Forward]
Beginning balance	236	220	220
Net proceeds from sales	(214)		(7)
Net gains (losses) on sales	5		1
Transfers in	0		28
Cash additions	0		0
Impairment charge	(27)		(6)
Ending balance	$ 0		236
Tax Lien
Real Estate Owned Disclosure [Line Items]
Number of Real Estate Properties | property	23
Foreclosed Property [Roll Forward]
Beginning balance	$ 3,300	$ 7,215	7,215
Net proceeds from sales	(1,916)		(5,458)
Net gains (losses) on sales	399		677
Transfers in	44		831
Cash additions	35		290
Impairment charge	(182)		(255)
Ending balance	$ 1,680		$ 3,300