Derivatives and Hedging Activities (Derivative Positions for Interest Rate Swaps which Qualify as Hedges) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Amortization Of Deferred Hedge Gains Losses	$ 0	$ 61,000
Change in Fair Value on Loans Held for Sale	1,000	$ (26,000)
Notional amount of fair value hedged derivative	$ 0		$ 0
Interest rate collars on loans [Member]
Derivatives, Fair Value [Line Items]
Derivative, Average Cap Interest Rate	3.02%		3.02%
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 250,000,000		$ 250,000,000
Derivative, Average Remaining Maturity	3 years 11 months 1 day		4 years 2 months 1 day
Derivative, Average Variable Interest Rate	2.49%		2.47%
Fair Value	$ 5,150,000		$ 3,344,000
Derivative, Average Floor Interest Rate	2.51%		2.51%
Interest rate swaps on loans [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 350,000,000		$ 250,000,000
Derivative, Average Remaining Maturity	4 years 2 months 23 days		4 years 6 months 7 days
Derivative, Average Variable Interest Rate	2.50%		2.57%
Derivative, Average Fixed Interest Rate	2.57%		2.67%
Fair Value	$ 6,458,000		$ 2,938,000
Interest rate swaps on borrowings [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 75,000,000		$ 75,000,000
Derivative, Average Remaining Maturity	2 years 11 months 4 days		3 years 2 months 4 days
Derivative, Average Variable Interest Rate	2.63%		2.74%
Derivative, Average Fixed Interest Rate	1.53%		1.53%
Fair Value	$ 1,528,000		$ 2,282,000
Interest rate swaps
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	675,000,000		575,000,000
Fair Value	$ 13,136,000		$ 8,564,000