Income Taxes - Components of Low Income Housing Investment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Taxes
Low income housing tax credits	$ 110	$ 111	$ 329	$ 333
Low income housing investment losses	$ 115	$ 118	$ 345	$ 353