Fair Value (Details 2) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Security	Dec. 31, 2016 USD ($) Security	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Breakdown of trust preferred securities
Number considered OTTI | Security	1	1
Trust preferred securities
Breakdown of trust preferred securities
Total number of trust preferred securities | Security	2	2
Par value, trust preferred securities	$ 1,939	$ 1,970
Number not considered OTTI | Security	1	1
Par value, trust preferred securities not considered OTTI	$ 903	$ 940
Number considered OTTI | Security	1	1
Par value, trust preferred securities considered OTTI	$ 1,036	$ 1,030
Life-to-date impairment recognized in earnings	140	140	$ 140	$ 140
Life-to-date impairment recognized in other comprehensive income	723	795
Total life-to-date impairment	$ 863	$ 935