Affordable Housing Tax Credit Limited Partnership (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Affordable housing tax credit investment	$ 3,000		$ 3,000
Less amortization	287		231
Net affordable housing tax credit investment	2,713		2,769
Unfunded commitment	$ 1,979		$ 2,257
Funding period for unfunded commitment (in years)	10 years
Tax credits and other tax benefits recognized	$ 56	$ 51
Tax credit amortization expense included in provision for income taxes	$ 56	$ 41