Income Taxes - Effective tax rate based upon total income tax provision (benefit) from continuing operations (Details 1)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal statutory rate	34.00%	34.00%
Business credits	(4.80%)	(2.20%)
ESOP dividend	(1.40%)	(1.20%)
Domestic production activities deduction	(2.40%)	(1.90%)
Stock compensation	(1.90%)
Revaluation of Deferred Taxes for Federal Tax Rate Change	12.60%	0.00%
Other	0.40%	0.30%
Effective tax rate	36.50%	29.00%