Derivatives - Fair Value Hedges on Balance Sheet (Details) - Interest Rate Swap, Liability [Member] - Designated as Hedging Instrument [Member] - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Weighted average remaining maturity	8 years 11 months 12 days	9 years 2 months 23 days
Weighted Average Pay Rate	3.09%	3.10%
Derivative liability, notional amount	$ 36,000,000	$ 35,000,000
Hedged liability, fair value	$ (2,063,000)	$ (1,174,000)