Derivatives and Hedging Activities (Derivative Positions for Interest Rate Swaps which Qualify as Hedges) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 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	$ 0	$ 183,000
Change in Fair Value on Loans Held for Sale	272,000	$ 103,000	1,192,000	$ 147,000
Notional amount of fair value hedged derivative	0		0		$ 0
Interest rate collars on loans [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Derivative, Notional Amount	$ 350,000,000		$ 350,000,000		$ 250,000,000
Derivative, Average Remaining Maturity	3 years 8 months 26 days				4 years 2 months 1 day
Derivative, Average Variable Interest Rate	2.03%		2.03%		2.47%
Fair Value	$ 12,913,000		$ 12,913,000		$ 3,344,000
Derivative, Average Cap Interest Rate	2.87%		2.87%		3.02%
Derivative, Average Floor Interest Rate	2.32%		2.32%		2.51%
Interest rate swaps on loans [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Derivative, Notional Amount	$ 400,000,000		$ 400,000,000		$ 250,000,000
Derivative, Average Remaining Maturity	3 years 9 months 3 days				4 years 6 months 7 days
Derivative, Average Variable Interest Rate	2.03%		2.03%		2.57%
Derivative, Average Fixed Interest Rate	2.47%		2.47%		2.67%
Fair Value	$ 16,389,000		$ 16,389,000		$ 2,938,000
Interest rate swaps on borrowings [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Derivative, Notional Amount	$ 75,000,000		$ 75,000,000		$ 75,000,000
Derivative, Average Remaining Maturity	2 years 5 months 4 days				3 years 2 months 4 days
Derivative, Average Variable Interest Rate	2.12%		2.12%		2.74%
Derivative, Average Fixed Interest Rate	1.53%		1.53%		1.53%
Fair Value	$ 5,000		$ 5,000		$ 2,282,000
Interest rate swaps
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Derivative, Notional Amount	825,000,000		825,000,000		575,000,000
Fair Value	$ 29,307,000		$ 29,307,000		$ 8,564,000