Financial Derivatives (Interest Rate Swaps) (Details) - Interest rate swaps $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Long
Derivative [Line Items]
Notional Amount	$ 132,273
Fair Value	1,664
Long | 2021 [Member]
Derivative [Line Items]
Notional Amount	12,500
Fair Value	23
Long | 2022 [Member]
Derivative [Line Items]
Notional Amount	53,974
Fair Value	309
Long | 2023 [Member]
Derivative [Line Items]
Notional Amount	48,657
Fair Value	803
Long | 2024 [Member]
Derivative [Line Items]
Notional Amount	11,342
Fair Value	456
Long | 2029 [Member]
Derivative [Line Items]
Notional Amount	5,800
Fair Value	$ 73
Long | Weighted Average
Derivative [Line Items]
Pay Rate	1.93%
Receive Rate	2.16%
Remaining Years to Maturity	3 years 102 days
Long | Weighted Average | 2021 [Member]
Derivative [Line Items]
Pay Rate	1.75%
Receive Rate	2.15%
Remaining Years to Maturity	1 year 354 days
Long | Weighted Average | 2022 [Member]
Derivative [Line Items]
Pay Rate	1.85%
Receive Rate	2.13%
Remaining Years to Maturity	2 years 153 days
Long | Weighted Average | 2023 [Member]
Derivative [Line Items]
Pay Rate	2.00%
Receive Rate	2.16%
Remaining Years to Maturity	3 years 186 days
Long | Weighted Average | 2024 [Member]
Derivative [Line Items]
Pay Rate	2.33%
Receive Rate	2.32%
Remaining Years to Maturity	4 years 175 days
Long | Weighted Average | 2029 [Member]
Derivative [Line Items]
Pay Rate	1.72%
Receive Rate	2.20%
Remaining Years to Maturity	9 years 318 days
Short
Derivative [Line Items]
Notional Amount	$ 583,914
Fair Value	(10,339)
Short | 2020 [Member]
Derivative [Line Items]
Notional Amount	68,607
Fair Value	92
Short | 2021 [Member]
Derivative [Line Items]
Notional Amount	169,567
Fair Value	(610)
Short | 2023 [Member]
Derivative [Line Items]
Notional Amount	101,012
Fair Value	(1,773)
Short | 2024 [Member]
Derivative [Line Items]
Notional Amount	52,426
Fair Value	(126)
Short | 2026 [Member]
Derivative [Line Items]
Notional Amount	73,782
Fair Value	1,059
Short | 2028 [Member]
Derivative [Line Items]
Notional Amount	32,942
Fair Value	(2,356)
Short | 2029 [Member]
Derivative [Line Items]
Notional Amount	76,773
Fair Value	(4,630)
Short | 2030 [Member]
Derivative [Line Items]
Notional Amount	685
Fair Value	(60)
Short | 2036 [Member]
Derivative [Line Items]
Notional Amount	1,100
Fair Value	33
Short | 2049 [Member]
Derivative [Line Items]
Notional Amount	7,020
Fair Value	$ (1,968)
Short | Weighted Average
Derivative [Line Items]
Pay Rate	1.98%
Receive Rate	2.19%
Remaining Years to Maturity	4 years 218 days
Short | Weighted Average | 2020 [Member]
Derivative [Line Items]
Pay Rate	1.74%
Receive Rate	2.16%
Remaining Years to Maturity	183 days
Short | Weighted Average | 2021 [Member]
Derivative [Line Items]
Pay Rate	1.86%
Receive Rate	2.19%
Remaining Years to Maturity	1 year 277 days
Short | Weighted Average | 2023 [Member]
Derivative [Line Items]
Pay Rate	2.06%
Receive Rate	2.18%
Remaining Years to Maturity	3 years 197 days
Short | Weighted Average | 2024 [Member]
Derivative [Line Items]
Pay Rate	1.72%
Receive Rate	2.24%
Remaining Years to Maturity	4 years 248 days
Short | Weighted Average | 2026 [Member]
Derivative [Line Items]
Pay Rate	1.67%
Receive Rate	2.15%
Remaining Years to Maturity	6 years 274 days
Short | Weighted Average | 2028 [Member]
Derivative [Line Items]
Pay Rate	2.40%
Receive Rate	2.17%
Remaining Years to Maturity	8 years 215 days
Short | Weighted Average | 2029 [Member]
Derivative [Line Items]
Pay Rate	2.25%
Receive Rate	2.24%
Remaining Years to Maturity	9 years 212 days
Short | Weighted Average | 2030 [Member]
Derivative [Line Items]
Pay Rate	2.38%
Receive Rate	2.14%
Remaining Years to Maturity	11 years 55 days
Short | Weighted Average | 2036 [Member]
Derivative [Line Items]
Remaining Years to Maturity	16 years 142 days
Short | Weighted Average | 2049 [Member]
Derivative [Line Items]
Pay Rate	2.89%
Receive Rate	2.32%
Remaining Years to Maturity	29 years 102 days
Forward-starting interest rate swap [Member] | Short
Derivative [Line Items]
Notional Amount	$ 85,200
Fair Value	$ 1,300
Derivative fixed interest rate including forward-starting swaps	1.87%